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For one of the most famous and widely investigated intermediate-valence compound SmB6, we report the results of a precise experimental study of the pressure effect on magnetic susceptibility χ. The measurements of χ(P) were carried out under helium gas pressure P up to 2 kbar at fixed temperatures 78 and 300 K using a pendulum-type magnetometer. The observed pressure effect value, d lnχ/dP ∼ –6 Mbar–1, demonstrates a noticeable decrease in susceptibility under pressure, which is weakly dependent on temperature used. From model analysis of the experimental data, combined with the supplemented LSDA + U calculations of the electronic structure and van Vleck paramagnetism of the band states of SmB6, we have estimated the value of the initial pressure derivative for the intermediate valence of Sm. It is consistent with the literature data obtained by other methods and indicates an increase in valence with increasing pressure. It was shown that the valence of Sm and its pressure dependence are closely related to the detailed characteristics of the conduction band and 4f states. [ABSTRACT FROM AUTHOR]

Breaking the topological protection of surface states of topological insulators is an essential prerequisite for exploring their applications. This is achievable by magnetic doping, in reduced dimensions, and predictably by introducing disorder beyond a critical level. In certain cases, the former is also known to induce a transition from weak anti-localization (WAL) to weak localization (WL). Here, we report the occurrence of paramagnetism, hopping conduction, and WL in chemically prepared unannealed Dy x Bi 2 − x Se 3 (x = 0 , 0.1, and 0.3) nanoplates primarily via dc magnetization, resistivity, and magnetoconductance measurements. The paramagnetism in the magnetic-atom-free Bi 2 Se 3 nanoplates is ascribed, using density functional theory calculations, to the acquisition of magnetic moments by defects. The defect density in pure Bi 2 Se 3 is estimated to be high (∼ 10 19 defects/cm 3). Successive Dy doping brings in further incremental disorder, apart from the Dy atomic moments. The nanoplates are shown to sequentially exhibit thermally activated band conduction, nearest neighbor hopping, Mott variable range hopping (VRH), and Efros–Shklovskii VRH with decreasing temperature. WL is evident from the observed positive magnetoconductance. Annealing converts the WL behavior to WAL, arguably by setting in the topological protection on a substantial reduction of the disorder. [ABSTRACT FROM AUTHOR]

We report the decoupling of Gd–Cr magnetism and the resulting giant magnetocaloric effect in honeycomb-lattice tellurate GdCrTeO6. This compound adopts the hexagonal structure with the space group P-3. The susceptibility curve presents a paramagnetic behavior from room temperature to 2 K. Very intriguingly, however, the heat capacity measurement probes a λ-like peak at TN = 10 K, characterizing the long-range antiferromagnetic order. This suggests that the Gd and Cr sublattices are magnetically independent, i.e., the Gd ions are paramagnetic and the strong paramagnetism nearly masks the antiferromagnetic order of Cr ions, which is further evidenced by our ESR data. The maximum magnetic entropy change at 2 K is 41.8 J kg−1 K−1 in a field range of 0–7 T and 30.3 J kg−1 K−1 for 0–3 T, larger than those of most of the Gd oxides reported. The observed giant magnetocaloric effect is due to strong paramagnetism of Gd ions. [ABSTRACT FROM AUTHOR]

High-pressure neutron diffraction data from powder and single-crystal samples of atomically disordered (F m 3 ¯ m) and ordered (P m 3 ¯ m) Pd 3 Fe were collected up to pressures of 15 GPa, and high-pressure SQUID magnetometry data were collected up to 6 GPa. The data show a subtle decrease in the magnetic moment with applied pressure, resulting in a transition to a paramagnetic state by approximately 8 GPa at 300 K. Diffraction results have been used to determine the equation of state, resulting in a bulk modulus of 176.78(9) GPa for the disordered powder and 187.96(7) GPa for the ordered single-crystal samples, approximately 20% more compressible than previously reported from X-ray measurements. High-temperature superconducting quantum interference device magnetometry was used to confirm the ambient pressure Curie temperature of the sample (545 K), which was further investigated using high-temperature single-crystal neutron diffraction at ambient pressure. [ABSTRACT FROM AUTHOR]

A first-order magneto-structural transition from a ferromagnetic orthorhombic TiNiSi-type martensite phase to a paramagnetic hexagonal Ni 2 In-type austenite phase was observed in (MnNiSi) 0.65 (Fe 2 Ge) 0.35 . In this work, we demonstrate that the first-order magneto-structural transition temperature for a given composition is tunable over a wide temperature range through heat treatment and hydrostatic pressure. The first-order transition temperature was reduced by over 100 K as the annealing temperature went from 600 to 900 °C, and this first-order transition was converted to second order when the sample was annealed at 1000 °C. The maximum magnetic-induced isothermal entropy change with μ 0 Δ H = 7 T reaches − 58 J/kg K for the sample annealed at 600 °C, and the relative cooling power reaches 558 J/kg for the sample annealed at 700 °C. Similar to the influence of annealing temperatures, the first-order martensitic transition temperatures were reduced as the application of hydrostatic pressure increased until they were converted to second order. Our results suggest that the (MnNiSi) 0.65 (Fe 2 Ge) 0.35 system is a promising platform for tuning magneto-structural transitions and the associated magnetocaloric effects. Furthermore, a similar heat treatment methodology or application of hydrostatic pressure can be applied to MnNiSi-based shape memory alloys to tailor their working transition temperatures. [ABSTRACT FROM AUTHOR]

In this paper, the magnetic and electrocatalytic properties of hydrothermally grown transition metal doped (10% of Co, Ni, Fe, and Mn) 2H-MoS2 nanocrystals (NCs) with a particle size 25–30 nm are reported. The pristine 2H-MoS2 NCs showed a mixture of canted anti-ferromagnetic and ferromagnetic behavior. While Co, Ni, and Fe doped MoS2 NCs revealed room temperature ferromagnetism, Mn doped MoS2 NCs showed room temperature paramagnetism, predominantly. The ground state of all the materials is found to be canted-antiferromagnetic phase. To study electrocatalytic performance for hydrogen evolution reaction, polarization curves were measured for undoped and the doped MoS2 NCs. At the overpotential of η = −300 mV, the current densities, listed from greatest to least, are FeMoS2, CoMoS2, MoS2, NiMoS2, and MnMoS2, and the order of catalytic activity found from Tafel slopes is CoMoS2 > MoS2 > NiMoS2 > FeMoS2 > MnMoS2. The increasing number of catalytically active sites in Co doped MoS2 NCs might be responsible for their superior electrocatalytic activity. The present results show that the magnetic order-disorder behavior and catalytic activity can be modulated by choosing the suitable dopants in NCs of 2D materials. [ABSTRACT FROM AUTHOR]

The crystal structure, and cryogenic magnetic and magnetocaloric properties in RE2T2Al (RE = Dy, Ho, Er, and Tm; T = Co and Ni) compounds have been investigated. All the compounds belong to an orthorhombic W2B2Co-type structure (Immm space group). A second order paramagnetic to ferromagnetic phase transition exists for RE2Co2Al compounds at TC = 62, 27, 32, and 11.5 K, whereas the compounds of RE2Ni2Al undergo a paramagnetic to antiferromagnetic phase transition with the Néel temperatures (TN) of 19, 12, 12.5, and 6 K for RE = Dy, Ho, Er, and Tm, respectively. Moreover, an additional low temperature magnetic transition occurs for all present RE2T2Al compounds. An obvious hysteresis was observed at a low temperature in the Dy2Co2Al, Ho2Co2Al, and Er2Co2Al compounds. The values of the maximum magnetic entropy change (−ΔSMmax) are 10.4, 11.5, 5.9, 7.7, 6.0, and 16.2 J/kg K for Dy2Co2Al, Ho2Co2Al, Er2Co2Al, Tm2Co2Al, Ho2Ni2Al, and Er2Ni2Al compounds with a field change (ΔH) of 0-5 T, respectively. Moreover, two peaks (or shoulder) in the −ΔSM (T) curves of Ho2Co2Al can be observed, which lead to a wide cooling temperature interval. [ABSTRACT FROM AUTHOR]

Enhancing the long term stable performance of silicon detectors used for monitoring the position and flux of the particle beams in high energy physics experiments requires a better knowledge of the nature, stability, and transformation properties of the radiation defects created over the operation time. We report the results of an electron spin resonance investigation in the nature, transformation, and long term stability of the irradiation paramagnetic point defects (IPPDs) produced by high fluence (2 × 1016 cm−2), high energy (27 MeV) electrons in n-type, P-doped standard floating zone silicon. We found out that both freshly irradiated and aged (i.e., stored after irradiation for 3.5 years at 250 K) samples mainly contain negatively charged tetravacancy and pentavacancy defects in the first case and tetravacancy defects in the second one. The fact that such small cluster vacancy defects have not been observed by irradiation with low energy (below 5 MeV) electrons, but were abundantly produced by irradiation with neutrons, strongly suggests the presence of the same mechanism of direct formation of small vacancy clusters by irradiation with neutrons and high energy, high fluence electrons, in agreement with theoretical predictions. Differences in the nature and annealing properties of the IPPDs observed between the 27 MeV electrons freshly irradiated, and irradiated and aged samples were attributed to the presence of a high concentration of divacancies in the freshly irradiated samples, defects which transform during storage at 250 K through diffusion and recombination processes. [ABSTRACT FROM AUTHOR]

By the controlling of oxygen flow rate, the oxygen content has been altered in the (CoFeTaB)(100−x)Ox system, a newly reported possible magnetic semiconductor. The electric and magnetic properties of (CoFeTaB)(100−x)Ox films are dependent on the oxygen content of (CoFeTaB)(100−x)Ox films. The resistivity of the grown (CoFeTaB)(100−x)Ox films could be altered from 3.77×10−4 Ω⋅cm to insulator. Correspondingly, the magnetic behavior of the grown (CoFeTaB)(100−x)Ox films was varied from ferromagnetism to paramagnetism. The increase in the resistivity was mainly attributed to the enhanced oxidization of metal Co; and the magnetism conversion was resulted from the decrease of ferromagnetic Fe3+ and increase of paramagnetic Co2+ in the grown films. These findings provide the fundamental reference for tailoring the electric and magnetic properties of (CoFeTaB)(100−x)Ox materials for potential applications in spintronics. [ABSTRACT FROM AUTHOR]

A large rotating magnetocaloric effect (RMCE) was always observed in the materials with anisotropic magnetisms, for example, ferromagnetism vs antiferromagnetism or paramagnetism, at different crystallographic directions. In this work, anisotropic ferromagnetic susceptibility is utilized to implement low-field (≤2 T) large RMCE in the textured polycrystalline HoB2 alloy. The x-ray diffraction and scanning electron microstructure results reveal that the arc-melted HoB2 exhibits preferred grain orientation along the solidification direction. The measured rotating magnetic entropy changes (−ΔSR) and refrigeration capacity are 6.27 J/kg K and 73.7 J/kg, respectively, under the magnetic field change of 1 T. They are comparable with those of other materials contributed by anisotropic magnetisms. Our results suggest that the polycrystal HoB2 alloy is a promising material for practical application of magnetic refrigeration based on RMCE. [ABSTRACT FROM AUTHOR]

Paramagnetic colloidal particles distributed along an ellipse are used as a model system to study the effects of curvature gradients on the structure and dynamics of colloids in curved manifolds. Unlike what happens for circular and spherical systems, in the present case, the equilibrium one-particle distribution function displays inhomogeneities due to the changing curvature along the ellipse. The ensuing effects on the two-body correlations are also analyzed, leading to the observation of anisotropic and long-ranged effects. Another noticeable consequence is the slowing down of the self-diffusion of these particles, which for large eccentricities may induce metastable states; this is evaluated by means of the time-dependent self-distribution. [ABSTRACT FROM AUTHOR]

We present a parallel implementation to compute electron spin resonance g-tensors at the coupledcluster singles and doubles (CCSD) level which employs the ACES III domain-specific software tools for scalable parallel programming, i.e., the super instruction architecture language and processor (SIAL and SIP), respectively. A unique feature of the present implementation is the exact (not approximated) inclusion of the five one- and two-particle contributions to the g-tensor [i.e., the mass correction, one- and two-particle paramagnetic spin-orbit, and one- and two-particle diamagnetic spin-orbit terms]. Like in a previous implementation with effective one-electron operators [J. Gauss et al., J. Phys. Chem. A 113, 11541-11549 (2009)], our implementation utilizes analytic CC second derivatives and, therefore, classifies as a true CC linear-response treatment. Therefore, our implementation can unambiguously appraise the accuracy of less costly effective one-particle schemes and provide a rationale for their widespread use. We have considered a large selection of radicals used previously for benchmarking purposes including those studied in earlier work and conclude that at the CCSD level, the effective one-particle scheme satisfactorily captures the two-particle effects less costly than the rigorous two-particle scheme. With respect to the performance of density functional theory (DFT), we note that results obtained with the B3LYP functional exhibit the best agreement with our CCSD results. However, in general, the CCSD results agree better with the experimental data than the best DFT/B3LYP results, although in most cases within the rather large experimental error bars. [ABSTRACT FROM AUTHOR]

SrTiO3 is a widely used substrate for the growth of other functional oxide thin films. The reactivity of the substrate with respect to the film during deposition, particularly with regard to redox reactions, has typically been glossed over. We demonstrate by depositing a variety of metals (Ti, Al, Nb, Pt, Eu, and Sr) and measuring the in situ core level spectra of both the metal and SrTiO3 that, depending on the oxide formation energy and work function of the metal, three distinct types of behavior occur in thin metal films on SrTiO3 (100). In many cases, there will be an interfacial layer of oxygen-deficient SrTiO3 formed at the interface with the overlying film. We discuss how this may affect the interpretation of the well-known two-dimensional electron gas present at the interface between SrTiO3 and various oxides. [ABSTRACT FROM AUTHOR]

The direct random phase approximation (RPA) and RPA with second-order screened exchange (SOSEX) have been implemented with complex orbitals as a basis for treating open-shell atoms. Both RPA and RPA+SOSEX are natural implicit current density functionals because the paramagnetic current density implicitly is included through the use of complex orbitals. We confirm that inclusion of the SOSEX correction improves the total energy accuracy substantially compared to RPA, especially for smaller-Z atoms. Computational complexity makes post self-consistent-field (post-SCF) evaluation of RPA-type expressions commonplace, so orbital basis origins and properties become important. Sizable differences are found in correlation energies, total atomic energies, and ionization energies for RPA-type functionals evaluated in the post-SCF fashion with orbital sets obtained from different schemes. Reference orbitals from Kohn-Sham calculations with semi-local functionals are more suitable for RPA+SOSEX to generate accurate total energies, but reference orbitals from exact exchange (non-local) yield essentially energetically degenerate open-shell atom ground states. RPA+SOSEX correlation combined with exact exchange calculated from a hybrid reference orbital set (half the exchange calculated from exact-exchange orbitals, the other half of the exchange from orbitals optimized for the Perdew-Burke-Ernzerhof (PBE) exchange functional) gives the best overall performance. Numerical results showthat the RPA-like functional with SOSEX correction can be used as a practical implicit current density functional when current effects should be included. [ABSTRACT FROM AUTHOR]

In this contribution, negative charges and electronic traps related to the Si/Al2O3 interface were measured and related to paramagnetic point defects and molecular vibrations. To this end, contactless capacitance voltage measurements, X-band electron paramagnetic resonance (EPR), and infrared spectroscopy were carried out, and their results were compared. A change in the negative charge density and electron trap density at the Si/Al2O3 interface was achieved by adding a thermally grown SiO2 layer with varying thicknesses and conducting an additional temperature treatment. Using EPR, five paramagnetic moments were detected in Si/(SiO2)/Al2O3 samples with g values of g1=2.0081±0.0002, g2=2.0054±0.0002, g3=2.0003±0.0002, g4=2.0026±0.0002 g5=2.0029±0.0002. Variation of the Al2O3 layer thickness shows that paramagnetic species associated with g1, g2, and g3 are located at the Si/Al2O3 interface, and those with g4 and g5 are located within the bulk Al2O3. Furthermore, g1, g2, and g3 were shown to originate from oxygen plasma exposure during Al2O3 deposition. Comparing the g values and their location within the Si/Al2O3 system, g1 and g3 can be attributed to Pb0 centers, g3 to Si dangling bonds (Si-dbs), and g4 and g5 to rotating methyl radicals. All paramagnetic moments observed in this contribution disappear after a 5-min temperature treatment at 450°C. The deposition of an additional thermal SiO2 layer between the Si and the Al2O3 decreases the negative fixed charge density and defect density by about one order of magnitude. In this contribution, these changes can be correlated with a decrease in amplitude of the Si-db signal. Pb0 and the methyl radical signals were less affected by this additional SiO2 layer. Based on these observations, microscopic models for the negative fixed charge density (Qtot) and the interface trap density (Dit) and the connection between these values are proposed. [ABSTRACT FROM AUTHOR]

Rare-earth orthoniobates constitute a class of materials that has been exploited due to their interesting physical properties depending on the lanthanide element. Besides paramagnetism, ferroelasticity, and negative compressibility, these materials are known by their interesting optical properties and mixed types of conduction processes (protonic, ionic, and electronic). In this work, two types of SmNbO4 samples were studied: polycrystalline samples, prepared by a sol-gel route using the Pechini method, and single crystalline fibres grown by the Laser Floating Zone technique. These samples were structurally characterized based on powder and single-crystal X-ray diffraction studies. A metastable tetragonal phase, stabilized by grain size, was identified in the synthesized powders. After a sintering process of such powders, a single monoclinic phase was obtained. Complementarily, scanning electron microscopy and Raman spectroscopy analyses were performed to these samples. Photoluminescence and photoluminescence excitation spectroscopic studies allowed identifying more than one optically active centre of the trivalent samarium ion in the analysed material. Impedance spectroscopy measurements have shown a large variation of the ac conductivity as a function of temperature, assigned to a protonic conduction and to native ionic conduction mechanisms. [ABSTRACT FROM AUTHOR]

This paper describes the unusual phenomenon of electromagnetic induction that occurs when a Nd–Fe–B magnet is passed through a hollow paramagnetic aluminum tube and conduction of eddy current happens. It was observed that the time taken by the Nd–Fe–B magnet to pass through a 1 m aluminum tube is longer than that through a 2 m tube. A tentative theory for this phenomenon is that due to the paramagnetism of the aluminum tube, the 2 m tube induces a more potent induction to pull the Nd–Fe–B magnet downward than that present in the 1 m tube. This scientific effect, which is coined herein as a length-boost effect, can create a situation that contradicts the conventional thinking that it should take a longer time to fall through a longer tube. One application of this is in controlling the velocity of a falling Nd–Fe–B magnet by changing the length of the aluminum pipe. The other is using aluminum as braking fins in free-fall chairs at amusement parks to reduce heat dissipation. However, diamagnetic tubes, such as those composed of copper and brass, do not possess this effect. A magnet falling through longer tubes of these metals takes a longer time than through shorter tubes. [ABSTRACT FROM AUTHOR]

The temperature dependent susceptibility and specific heat of spinel compound CdV2O4 were investigated. The structural transition accompanied with orbital order appearing at 89.6K is confirmed to be a first order transition, while the magnetic transitions at 30.2K is revealed to be a second order one. For the paramagnetism-antiferromagnetic transition, the width of critical region was estimated to be about 1.5K by differentiating with Gaussian fluctuation. In critical region, the critical behavior of specific heat was compared with renormalization-group theory. Critical exponent α and critical amplitude ratio (A+/A–) fitting to the data was found to be –0.017 and 1.26, respectively. The value of A+/A– shows the critical behavior of CdV2O4's deviates from 3D-Heisenberg and shifts to 3D-XY. The analysis of specific heat in low temperature range gives out that Debye temperature ϴD for CdV2O4 is estimated to be 190 K. [ABSTRACT FROM AUTHOR]

The structure of known Gd4Co3 compound is re-determined as Gd6Co4.85, adopting the Gd6Co1.67Si3 structure type, which is characterized by two disorder Co sites filling the Gd octahedral and a short Gd-Gd distance within the octahedra. The compound shows uniaxial negative thermal expansion in paramagnetic state, significant negative expansion in ferromagnetic state, and positive expansion below ca. 140 K. It also exhibits large magnetocaloric effect, with an entropy change of –6.4 J kg–1K–1 at 50 kOe. In the lattice of the compound, Co atoms at different sites show different spin states. It was confirmed by the X-ray photoelectron spectra and calculation of electronic structure and shed lights on the abnormal thermal expansion. The stability of such compound and the origin of its magnetism are also discussed based on measured and calculated electronic structures. [ABSTRACT FROM AUTHOR]

We study and compare magnetic and electron paramagnetic resonance behaviors of bulk and nanoparticles of Nd1-xCaxMnO3 in hole doped (x=0.4;NCMOH) and electron doped (x=0.6;NCMOE) samples. NCMOH in bulk form shows a complex temperature dependence of magnetization M(T), with a charge ordering transition at ∼250 K, an antiferromagnetic (AFM) transition at ∼150 K, and a transition to a canted AFM phase/mixed phase at ∼80 K. Bulk NCMOE behaves quite differently with just a charge ordering transition at ∼280 K, thus providing a striking example of the so called electron-hole asymmetry. While our magnetization data on bulk samples are consistent with the earlier reports, the new results on the nanoparticles bring out drastic effects of size reduction. They show that M(T) behaviors of the two nanosamples are essentially similar in addition to the absence of the charge order in them thus providing strong evidence for vanishing of the electron-hole asymmetry in nanomanganites. This conclusion is further corroborated by electron paramagnetic resonance studies which show that the large difference in the "g" values and their temperature dependences found for the two bulk samples disappears as they approach a common behavior in the corresponding nanosamples. [ABSTRACT FROM AUTHOR]

Anisotropic interactions present in three new nitroxide radicals prepared by N,N addition of NO to various borane-phosphane frustrated Lewis pairs (FLPs) have been characterized by continuous-wave (cw) and pulsed X-band EPR spectroscopies in solid FLP-hydroxylamine matrices at 100 K. Anisotropic g-tensor values and 11B, 14N, and 31P hyperfine coupling tensor components have been extracted from continuous-wave lineshape analyses, electron spin echo envelope modulation (ESEEM), and hyperfine sublevel correlation spectroscopy (HYSCORE) experiments with the help of computer simulation techniques. Suitable fitting constraints are developed on the basis of density functional theory (DFT) calculations. These calculations reveal that different from the situation in standard nitroxide radicals (TEMPO), the g-tensors are non-coincident with any of the nuclear hyperfine interaction tensors. The determination of these interaction parameters turns out to be successful, as the cw- and pulse EPR experiments are highly complementary in informational content. While the continuous-wave lineshape is largely influenced by the anisotropic hyperfine coupling to 14N and 31P, the ESEEM and HYSCORE spectra contain important information about the 11B hyperfine coupling and nuclear electric quadrupolar interaction. The set of cw- and pulsed EPR experiments, with fitting constraints developed by DFT calculations, defines an efficient strategy for the structural analysis of paramagnetic FLP adducts. [ABSTRACT FROM AUTHOR]

The magnetic properties of low filling factor Fe-nanoparticle monolayers separated by relatively thick Al2O3 layers were investigated in parallel and perpendicular external magnetic field. The thin film nanocomposites were prepared by sequential pulsed laser deposition on (100) Si substrates, and the monolayers contain single-domain, dispersive nanoparticles. When the magnetic field is oriented parallel to the layers, the composite exhibits superparamagnetism. However, in perpendicular field, the superferromagnetic order sets in, as revealed by the increase of the magnetic moment, the hysteresis persisting at high temperatures, and a smaller relaxation rate. The complex out of plane behavior of our nanocomposites in perpendicular field is attributed to quasi two-dimensionality and to the dispersion of the in-plane nanoparticle separation. [ABSTRACT FROM AUTHOR]

The concentration of excitons generated in a high-quality diamond p-i-n junction is investigated considering the forward current characteristics of the junction. As the forward current in the junction increases, the exciton concentration increases superlinearly, contrary to the linear increases of the electron and hole concentration. This tendency suggests a superlinear increase in emission intensity due to exciton recombination. The increase rate is more radical than quadratic, in accordance with the observed increase of the integrated intensity of free exciton emission. To estimate the concentration of triplet excitons generated in the p-i-n junction, observation of the paramagnetism due to the exciton spin moment is proposed. The magnetic susceptibility superlinearly increases with the increase in the forward current, unlike any other magnetic property of the device. [ABSTRACT FROM AUTHOR]

The zero-field splitting (ZFS) of the electronic ground state in paramagnetic ions is a sensitive probe of the variations in the electronic and molecular structure with an impact on fields ranging from fundamental physical chemistry to medical applications. A detailed analysis of the ZFS in a series of symmetric Gd(III) complexes is presented in order to establish the applicability and accuracy of computational methods using multiconfigurational complete-active-space self-consistent field wave functions and of density functional theory calculations. The various computational schemes are then applied to larger complexes Gd(III)DOTA(H2O)-, Gd(m)DTPA(H2O)2-, and Gd(HI)(H2O)3+8 in order to analyze how the theoretical results compare to experimentally derived parameters. In contrast to approximations based on density functional theory, the multiconfigurational methods produce results for the ZFS of Gd(III) complexes on the correct order of magnitude. [ABSTRACT FROM AUTHOR]

A new two-dimensional Nuclear Magnetic Resonance (NMR) experiment to separate and correlate the first-order quadrupolar and chemical/paramagnetic shift interactions is described. This experiment, which we call the shifting-d echo experiment, allows a more precise determination of tensor principal components values and their relative orientation. It is designed using the recently introduced symmetry pathway concept. A comparison of the shifting-d experiment with earlier proposed methods is presented and experimentally illustrated in the case of ²H (I = 1) paramagnetic shift and quadrupolar tensors of CuCl2·2D2O. The benefits of the shifting-d echo experiment over other methods are a factor of two improvement in sensitivity and the suppression of major artifacts. From the 2D lineshape analysis of the shifting-d spectrum, the ²H quadrupolar coupling parameters are (Cq) = 118.1 kHz and (ηq) = 0.88, and the ²H paramagnetic shift tensor anisotropy parameters are (ζP) = -152.5 ppm and (ηP) = 0.91. The orientation of the quadrupolar coupling principal axis system (PAS) relative to the paramagnetic shift anisotropy principal axis system is given by (α,β,γ) = (π/2, π/2, 0). Using a simple ligand hopping model, the tensor parameters in the absence of exchange are estimated. On the basis of this analysis, the instantaneous principal components and orientation of the quadrupolar coupling are found to be in excellent agreement with previous measurements. A new point dipole model for predicting the paramagnetic shift tensor is proposed yielding significantly better agreement than previously used models. In the new model, the dipoles are displaced from nuclei at positions associated with high electron density in the singly occupied molecular orbital predicted from ligand field theory. [ABSTRACT FROM AUTHOR]

The magnetically actuated robot has valuable potential in biomedicine, bioengineering, and biophysics for its capability to precisely manipulate particles or biological tissues. However, the deformability of rigid robots with predetermined shapes is limited, which constricts their functions and causes inconvenience for robots' movement in constricted space. In this study, we proposed a feasible and efficient ferrofluid-based robot for the transportation of tiny particles and blocks. In addition, a method to generate a patterned magnetic field is also introduced to model a ferrofluid-based robot with an adaptive shape. Benefiting from the paramagnetism and fluidity of the ferrofluid-based robot, it also demonstrates outstanding motion accuracy and output force on a superhydrophobic surface. Because of its excellent motion characteristics, high motion accuracy, and high measured output force, the proposed ferrofluid-based robot has great advantages in the field of microoperation. The correlation coefficient between the motion trajectory of the ferrofluid-based robot and the motion trajectory of the micro-stages is 0.9967. The position error is less than 1.5% of the total stroke. [ABSTRACT FROM AUTHOR]

Magnetic dynamics studies by AC susceptibility technique have been performed on the two newest-generation iron deficiency drugs, commercialized under the trade names Feraheme and Monofer. In all aspects, these magnetic nanoparticle systems obey a common pattern of superparamagnetism characterized by similar blocking temperatures, average particle sizes, and magnetocrystalline anisotropy energy. However, effective magnetic moments associated with average particle of each drug are remarkably different, being approximately 10630 μB (Feraheme) and 134 μB (Monofer). The difference relies on qualitatively different magnetic interaction permeating the iron cores of the constituent nanoparticles. The nanoparticle of each system can be classified as monodomain ferrimagnet (Feraheme) and almost compensated antiferromagnet (Monofer). In accordance with different associated moments the dipole-dipole interaction between nanoparticles for the two drugs differs for orders of magnitudes but remains safely small at room temperatures. For reference, the corresponding measurements on previously better investigated iron-sucrose haematinic Venofer has been also performed and included in this article. [ABSTRACT FROM AUTHOR]

We report a systematic study of the specific heat and dc magnetic susceptibility on the paramagnetic to ferrimagnetic transition (TC~141 K) in CuNMn3. A large magnetocaloric effect (MCE) at TC is observed with the entropy change of 3.49 J/kg K (6.38 J/kg K) for the field change of ΔH=20 kOe (45 kOe). The analysis of the isothermal magnetizations, including the derived Arrott plots and magnetic entropy change, shows a second-order like transition at TC. However, the existence of latent heat around TC is unambiguously manifested by the reduced slope of the temperature-time relaxations recorded during the specific heat measurement, indicating the transition is in fact weakly first-order in nature. The large MCE comparable with those observed the antiperovskite manganese carbides suggests it is equivalently interesting to explore the MCE in the antiperovskite manganese nitrides as in the carbides. [ABSTRACT FROM AUTHOR]

We present a method for a subsystem-based calculation of indirect nuclear spin-spin coupling tensors within the framework of current-spin-density-functional theory. Our approach is based on the frozen-density embedding scheme within density-functional theory and extends a previously reported subsystem-based approach for the calculation of nuclear magnetic resonance shielding tensors to magnetic fields which couple not only to orbital but also spin degrees of freedom. This leads to a formulation in which the electron density, the induced paramagnetic current, and the induced spin-magnetization density are calculated separately for the individual subsystems. This is particularly useful for the inclusion of environmental effects in the calculation of nuclear spin-spin coupling constants. Neglecting the induced paramagnetic current and spin-magnetization density in the environment due to the magnetic moments of the coupled nuclei leads to a very efficient method in which the computationally expensive response calculation has to be performed only for the subsystem of interest. We show that this approach leads to very good results for the calculation of solvent-induced shifts of nuclear spin-spin coupling constants in hydrogen-bonded systems. Also for systems with stronger interactions, frozen-density embedding performs remarkably well, given the approximate nature of currently available functionals for the non-additive kinetic energy. As an example we show results for methylmercury halides which exhibit an exceptionally large shift of the one-bond coupling constants between 199 Hg and 13C upon coordination of dimethylsulfoxide solvent molecules. [ABSTRACT FROM AUTHOR]

The origin of negative thermal expansion (NTE) in the bond frustrated ZnCr2Se4 has been explored. ESR and FTIR document an ideal paramagnetic state above 100 K, below which ferromagnetic clusters coexist with the paramagnetic state down to TN. By fitting the inverse susceptibility above 100K using a modified paramagnetic Curie-Weiss law, an exponentially changeable exchange integral J is deduced. In the case of the variable J, magnetic exchange and lattice elastic energy couple with each other effectively via magnetoelastic interaction in the ferromagnetic clusters, where NTE occurs at a loss of exchange energy while a gain of lattice elastic one. [ABSTRACT FROM AUTHOR]

This work presents a detailed study on the critical behavior of the ferromagnetic-paramagnetic (FM-PM) phase transition in Fe90_xNixZr10 (x=0 and 5) alloy ribbons. Basing on field dependences of magnetization (M-H), M² versus H/M plots prove the alloys exhibiting a second-order magnetic phase transition. To investigate the nature of the FM-PM phase transition at TC = 245 and 306 K for x= 0 and 5, respectively, we performed a critical-exponent study. The values of critical components β, γ, and δ determined by using the modified Arrott plots, Kouvel-Fisher (KF), and critical isotherm analyses agree with each other. For x = 0, the critical parameters β = 0.365 6 0.013 and γ = 1.615 ± 0.033 are obtained by modified Arrott plots while γ = 0.368 6 0.008 and γ = 1.612 6 0.016 are obtained by the KF method. These values are close to those expected for the 3D-Heisenberg model, revealing short-range FM interactions in Fe90Zr10. Meanwhile, for x=5, the values of the critical parameters β = 0.423 6 0.008 and δ = 1.325 6 0.036 are obtained by modified Arrott plots, and P = 0.425 6 0.006 and γ = 1.323 6 0.012 are obtained by the KF method. The falling of the γ value in between the values of the mean-field theory (β = 0.5) and the 3D-Heisenberg model (β = 0.365) indicates an existence of FM short-range order and magnetic inhomogeneity in Fe85Ni5Zr10. With a partial replacement of Ni for Fe in Fe90_xNixZr10, the value of the critical exponent γ trends to shift towards that of the mean-field theory. Such the result proves the presence of Ni favors establishing FM long-range order. The nature of this phenomenon is carefully discussed. [ABSTRACT FROM AUTHOR]

We study planar defects in epitaxial Co:ZnO dilute magnetic semiconductor thin films deposited on c-plane sapphire (Al2O3), as well as the Co:ZnO/Al2O3 interface, using aberration-corrected transmission electron microscopy and electron energy-loss spectroscopy. Co:ZnO samples that were deposited using pulsed laser deposition and reactive magnetron sputtering are both found to contain extrinsic stacking faults, incoherent interface structures, and compositional variations within the first 3-4 Co:ZnO layers next to the Al2O3 substrate. The stacking fault density is in the range of 1017 cm-3. We also measure the local lattice distortions around the stacking faults. It is shown that despite the relatively high density of planar defects, lattice distortions, and small compositional variation, the Co:ZnO films retain paramagnetic properties. [ABSTRACT FROM AUTHOR]

Using the Lamb-dip technique, the hyperfine structure in the rotational spectra of H233S and 33SO2 has been resolved and the corresponding parameters-that is, the sulfur quadrupole-coupling and spin-rotation tensors-were determined. The experimental parameters are in good agreement with results from high-level coupled-cluster calculations, provided that up to quadruple excitations are considered in the cluster operator, sufficiently large basis sets are used, and vibrational corrections are accounted for. The 33S spin-rotation tensor for H2S has been used to establish a new sulfur nuclear magnetic shielding scale, combining the paramagnetic part of the shielding as obtained from the spin-rotation tensor with a calculated value for the diamagnetic part as well as computed vibrational and temperature corrections. The value of 716(5) ppm obtained in this way for the sulfur shielding of H2S is in good agreement with results from high-accuracy quantum-chemical calculations but leads to a shielding scale that is about 28 ppm lower than the one suggested previously in the literature, based on the 33S spin-rotation constant of OCS. [ABSTRACT FROM AUTHOR]

Bimagnetic materials were fabricated by decorating the external surface of rattle-type hollow silica microspheres (which themselves contain metallic cobalt nanoparticles) with magnetite nanoparticles; thus, each magnetic substance was spatially isolated by the silica shell. The amount of magnetite decoration on the co-occluded hollow silica was varied from 1 to 17 mass %. Magnetic and electronic properties of the resulting bimagnetic materials were characterized by superconducting quantum interference device measurements and X-ray absorption spectroscopy, respectively. The ferrous iron in the bimagnetic sample was slightly more oxidized than in the magnetite reference, probably from some charge-transfer because of the SiO2 surface contact, although the overall oxidation state of the samples is very similar to that of magnetite. The temperature dependence of the sample magnetization recorded with Zero Field Cooling and Field Cooling resulted in blocking temperatures for the bimagnetic materials that were close to that of magnetite nanoparticles (176 K) and were lower than that for the bare Co-occluded hollow silica (which was above room temperature). Values of coercive force and exchange bias at 300 K became quite small after decoration with only minimal amounts of magnetite nanoparticles (1-3 mass %) and were lower than those of magnetite. This is the first example of enhancing superparamagnetism by spatial separation of both Co and magnetite magnetic nanoparticles using a thin wall of diamagnetic silica. [ABSTRACT FROM AUTHOR]

We present an experimental and theoretical study of Pauli paramagnetism and martensite stabilization in a near equiatomic NiTi shape memory alloy. We demonstrate a direct correlation between strain-induced shear of the B19′ NiTi lattice and its electronic and thermodynamical features. An increase in the monoclinic angle β from 97.4 to 98° induces a 7% decrease in the magnetic susceptibility because of a shift and deepening of a dip in B19′ density of states at the Fermi level. It also produces a decrease in the B19′ enthalpy, which translates into an increase in the martensite-to-austenite transition temperature by 60 K. [ABSTRACT FROM AUTHOR]

We report the effect of temperature on the crystallographic structure and magnetic properties of ultrasonically prepared nanostructured Nd0.7Sr0.3MnO3 perovskite manganite. The crystal structure of as-synthesized nanoparticles remains unaltered over a wide scanning temperature range. Temperature dependent magnetization measurements demonstrate that the Curie temperature (Tc) of Nd0.7Sr0.3MnO3 nanoparticles is in the range of 211 K–220 K under largely varying applied magnetic fields. Below Tc, the soft ferromagnetic nature of these nanoparticles is confirmed by the field-dependent magnetization measurements. The absence of the charge-ordered state is also revealed in this nanomanganite down to 20 K, which is strikingly different from analogous Nd–Sr based nanocrystals. The experimentally observed effective paramagnetic moment and saturation magnetic moment have matched quite well with the values calculated theoretically. The Tc values up to a temperature of 220 K, nearly perfect ferromagnetically ordered Mn ions below Tc, high saturation magnetization, and magnetic softness of synthesized nanostructured Nd0.7Sr0.3MnO3 manganite can be associated with their good crystallinity as well as the nominal internal and surface disorder effect owing to intermediate particle size (∼75 nm to 150 nm). Our investigation elucidates the promising potential of nanocrystalline Nd0.7Sr0.3MnO3 particles for numerous technological applications. [ABSTRACT FROM AUTHOR]

The effect of deposition oxygen pressure (PO) on phase separation (PS) induced in epitaxial La0.67Ca0.33MnO3/NdGaO3(001) films was investigated. Fully oxygenated films grown at high PO are anisotropically strained. They exhibit PS over a wide temperature range, because of the large orthorhombicity of NdGaO3 substrates. The paramagnetic insulator-to-ferromagnetic metal (FM) and FM-to-antiferromagnetic insulator (AFI) transitions gradually shift to lower temperatures with decreasing PO. The AFI state is initially weakened (PO ≥ 30 Pa), but then becomes more robust against the magnetic field (PO < 30 Pa). The out-of-plane film lattice parameter increases with decreasing PO. For films grown at PO ≥ 30 Pa, the slight oxygen deficiency may enlarge the lattice unit cell, reduce the anisotropic strain, and suppress the AFI state. Films deposited at PO < 30 Pa instead experience an average compressive strain. The enhanced compressive strain and structural defects in the films may lead to the robust AFI state. These results aid our understanding of PS in manganite films. [ABSTRACT FROM AUTHOR]

We study spin excitations of the fully aligned state for three-dimensional nanocomposites of exchange coupled hard (SmFeN) and soft (FeCo) phases. The dipolar interaction lowers the magnon energy and controls the spin wave gap at k = 0, which closes when the amount of soft phase exceeds a critical value. With the addition of soft phase or increasing temperature the system moves to another ground state characterized by a tilting of the magnetization at the boundaries between spins of the hard and the soft phases. [ABSTRACT FROM AUTHOR]

While charge-ordering transition is well established in the oxygen-deficient layered cobaltite YBaCo2O5, there has been no evidence for the transition in the analogous compound GdBaCo2O5 either from neutron diffraction or from magnetic susceptibility experiments. In this paper, we present comparative studies on the electron spin resonance (ESR) of Gd3+ ions in Y1-xGdxBaCo2O5 (x = 0.01, 0.25, and 1) polycrystalline samples. Magnetic susceptibility was also performed for comparison with the ESR results. It was found that charge-ordering transition for Y0.75Gd0.25BaCo2O5 revealed by the susceptibility is also manifested in the characters of the ESR data. The similar temperature-evolution of the ESR parameters for GdBaCo2O5 provides a support for the existence of charge-ordering transition, although no characteristic of the transition is evidenced from susceptibility experiments, which can be understood as being hidden by dominant paramagnetism of Gd3+ ions in this compound. We have interpreted the temperature variation of ESR parameters in terms of electron localization associated with Co2+/Co3+ charge ordering. [ABSTRACT FROM AUTHOR]

We have investigated magnetization (M), magnetocaloric effect (MCE), and magnetothermopower (MTEP) in polycrystalline Pr0.6Sr0.4MnO3, which shows a second-order paramagnetic to ferromagnetic transition near room temperature (TC = 305 K). However, field-cooled M(T) within the long range ferromagnetic state shows an abrupt decrease at TS = 86 K for μ0H < 3 T. The low temperature transition is first-order in nature as suggested by the hysteresis in M(T) and exothermic/endothermic peaks in differential thermal analysis for cooling and warming cycles. The anomaly at TS is attributed to a structural transition from orthorhombic to monoclinic phase. The magnetic entropy change (ΔSm = Sm(μ0 H)-Sm(0)) shows a negative peak at TC (normal MCE) and a positive spike (inverse MCE) at TS. ΔSm = -2.185 J/kg K (-3.416 J/kg K) with refrigeration capacity RC = 43.4 J/kg (103.324 J/kg) for field change of μ0ΔH = 1.5 T (3 T) at TC = 304 K is one of the largest values reported in manganites near room temperature. Thermopower (Q) is negative from 350 K to 20 K, which shows a rapid decrease at TC and a small cusp around TS in zero field. The MTEP [ΔQ/Q(0)] reaches a maximum value of 25% for μ0ΔH = 3 T around TC, which is much higher than 15% dc magnetoresistance for the same field change. A linear relation between MTEP and magnetoresistance and between ΔSm and ΔQ are found near TC. Further, ac magnetotransport in low dc magnetic fields (μ0 H ≤ 0.1 T), critical analysis of the paramagnetic to ferromagnetic transition, and scaling behavior of ΔSm versus a reduced temperature under different magnetic fields are also reported. Coexistence of large magnetic entropy change and magnetothermopower around room temperature makes this compound interesting for applications. [ABSTRACT FROM AUTHOR]

It is proven that the common origin gauge proposed by Chan and Das for the calculation of molecular magnetizabilities within the conventional approach using gaugeless basis sets, i.e., the center of electronic charge, does not minimize the van Vleck paramagnetic contribution to the diagonal tensor components, unless the Arrighini-Maestro-Moccia sum rules for gauge invariance, and charge conservation are satisfied. Additional quantum mechanical constraints for extremum values of formally diamagnetic and paramagnetic contributions have also been obtained for magnetizabilities calculated via procedures allowing for a continuous translation of the origin of the current density. [ABSTRACT FROM AUTHOR]

We report the observation of reentrant spin glass state in the bilayered manganite with nominal composition La4/3Sr5/3Mn2O7. The studied compound transforms from a high temperature paramagnetic phase with antiferromagnetic type short range magnetic correlation to a ferromagnetic phase upon cooling. On further cooling, the long range ferromagnetic phase is destroyed leading to glassy magnetic phase. Our ac susceptibility analysis indicates the possibility of the existence of frozen spin clusters below the spin glass transition temperature. The cooling rate and cooling field dependence of magnetization measurements reveal that the glassy phase is closely connected with the arrested kinetics of the first order phase transition leading to the existence of antiferromagnetic/paramagnetic clusters along with the ferromagnetic phase at low temperature. [ABSTRACT FROM AUTHOR]

[Co0.4 nm/Pd0.7 nm]50 multilayers with Pd film thicknesses in the first ferromagnetic maximum of interlayer exchange coupling display almost purely perpendicular-to-plane anisotropy and labyrinth stripe domain patterns in remanence. Their magnetization reversal is characterized by domain nucleation starting at a defined field HN and domain wall movement in a defined magnetic field range. The modification of the magnetization reversal by 10 keV He ion bombardment due to the reduced magnetic anisotropy has been investigated by polar magneto-optical Kerr effect, by vibrating sample magnetometry, and by magnetic force microscopy at room temperature. It is shown that the ion bombardment creates and increases areas with ferromagnetic in-plane anisotropy and proportions of the sample showing superparamagnetism, the latter predominantly in the deeper layers. [ABSTRACT FROM AUTHOR]

We study the equation of state of the non-relativistic free-electron gas in a constant magnetic field at arbitrary degeneracy based on the seminal work of Biswas et al. [Phys. Plasmas 20, 052503 (2013)]. The approach naturally unifies the Pauli paramagnetism, the Landau diamagnetism, and the de Haas–van Alphen effect. We consider the magnetization and the susceptibility as well as various thermodynamic quantities. In particular, the specific heats at constant volume and constant pressure are calculated, from which the adiabatic index is obtained. Weak and strong field limits are examined in detail. It is shown that the various quantities of interest saturate at strong magnetic field. Results are consistent with previous calculations performed at zero magnetic field. The polylogarithms are more adapted than the Fermi–Dirac integrals to describe the present system. The de Haas–van Alphen effect is not restricted to the magnetization and susceptibility but can be seen for other thermodynamic quantities. [ABSTRACT FROM AUTHOR]

1H spin-lattice relaxation rates in glycerol solutions of selected nitroxide radicals at temperatures between 200 K and 400 K were measured at 15 MHz and 25 MHz. The frequency and temperature conditions were chosen in such a way that the relaxation rates go through their maximum values and are affected by neither the electron spin relaxation nor the electron-nitrogen nucleus hyperfine coupling, so that the focus could be put on the mechanisms of motion. By comparison with 1H spin-lattice relaxation results for pure glycerol, it has been demonstrated that the inter-molecular electron spin-proton spin dipole-dipole interactions are affected not only by relative translational motion of the solvent and solute molecules, but also by their rotational dynamics as the interacting spins are displaced from the molecular centers; the eccentricity effects are usually not taken into account. The 1H relaxation data have been decomposed into translational and rotational contributions and their relative importance as a function of frequency and temperature discussed in detail. It has been demonstrated that neglecting the rotational effects on the inter-molecular interactions leads to non-realistic conclusions regarding the translational dynamics of the paramagnetic molecules. [ABSTRACT FROM AUTHOR]

High-power impulse magnetron sputtering (HiPIMS) is a pulsed DC sputtering technique utilizing high power density peaks of typically more than 100 W cm-2. The discharge operation at such elevated powers can be hindered by the magnetron configuration (size and magnetic field) and/or the target conditions (e.g., material and thickness). In addition, target erosion is an important issue significantly affecting process reproducibility. In the present work, we propose a simple approach for the stabilization of the HiPIMS discharge by controlling the target magnetic field using paramagnetic spacers with different thicknesses in between the magnetron surface and the target. We demonstrate a straightforward discharge optimization, while using various target materials, such as Nb, Ta, Cr, Al, Ti, Si, and even C (graphite). The existence of a steady state high density discharge above the graphite target and the other targets in general is discussed in terms of the magnetic field configuration and the gas rarefaction effect. [ABSTRACT FROM AUTHOR]

In this work, we have studied the suppression of the charge-ordered (CO) state in Nd0.8Na0.2MnO3 compound by varying the particle size and the applied magnetic field. The bulk samples with a particle size of D ≥ 140 nm exhibit different magnetic ground states, such as paramagnetic (PM), charge-ordering, ferromagnetic-cluster-glass (FM-CG), and reentrant-spin-glass-like (RSG) behavior. The complete suppression of charge ordering could be observed by reducing the particle size down to 50 nm. The field variation of magnetization curves at different temperatures show field-induced reversible transition from the antiferromagnetic (AFM) CO state to the FM state beyond a threshold field (HC). The M-H loops recorded at 5 K, show a distinct field-induced transition from a spin-frozen state to a FM state, especially on bulk samples with particle sizes of D ≥ 140 nm. T-H phase diagrams were constructed for samples with different particle sizes. The phase boundary between CO-AFM and FM states was found to shift toward higher temperature and lower magnetic fields with a decrease in particle size. Moreover, the phase-separation region was also found to narrow down with a decrease in particle size. The boundary of the spin-frozen state is found to shift toward lower temperature and magnetic field with decrease in particle size. The observed result could be explained based on the core-shell model. [ABSTRACT FROM AUTHOR]

We have studied the effect of the yttria content on the paramagnetic centers in electron-irradiated yttria-stabilized zirconia (ZrO2: Y3+) or YSZ. Single crystals with 9.5 mol % or 18 mol % Y2O3 were irradiated with electrons of 1.0, 1.5, 2.0, and 2.5 MeV. The paramagnetic center production was studied by X-band electron paramagnetic resonance (EPR) spectroscopy. The same paramagnetic centers were identified for both chemical compositions, namely two electron centers, i.e., (i) F+-type centers (involving singly ionized oxygen vacancies), and (ii) so-called T centers (Zr3+ in a trigonal symmetry site), as well as hole-centers. A strong effect is observed on the production of hole-centers that is strongly enhanced when doubling the yttria content. However, no striking effect is found on the electron centers (except the enhancement of an extra line associated with the F+-type centers). It is concluded that hole-centers are produced by inelastic interactions, whereas F+-type centers are produced by elastic collisions with no effect of the yttria content on the defect production rate. In the latter case, the threshold displacement energy (Ed) of oxygen is estimated from the electron-energy dependence of the F+-type center production rate, with no significant effect of the yttria content on Ed. An Ed value larger than 120 eV is found. This is supported by classical molecular dynamics (MD) simulations with a Buckingham-type potential that show Ed values for Y and O are likely to be in excess of 200 eV. Due to the difficulty in displacing O or Y atoms, the radiation-induced defects may alternatively be a result of Zr atom displacements for Ed = 80 ± 1 eV with subsequent defect rearrangement. [ABSTRACT FROM AUTHOR]

An epitaxial La0.45Sr0.55MnO3 (LSMO) film, which has a paramagnetic-to-ferromagnetic transition at ∼260 K and a partial ferromagnetic-to-antiferromagnetic transition at ∼150 K upon cooling, was synthesized on (001) (La0.18Sr0.82)(Al0.59Ta0.41)O3 with pulsed laser deposition. The x-ray diffraction pattern showed interference fringes around the (002) LSMO peak, indicating a successful growth of a high quality and smooth film. When the LSMO film was cooled down in a magnetic field of 5 kOe, it exhibited a large exchange bias (HEX) of ∼490 Oe and an enhanced coercivity (HC) of ∼800 at 10 K, respectively. The observed exchange bias effect, which is associated with phase coexistence of the ferromagnetic (FM) and antiferromagnetic (AF) phases, displayed a distinctive training effect, which is probably due to a competing spin order at the boundary between the FM and AF phases. Similarly, we also observed a large exchange bias and enhanced coercivity in a phase separated Pr0.55(Ca0.65S0.35)0.45MnO3 film, which had simultaneous FM and AF transitions at ∼150 K. Our results show that the exchange bias effect can be induced even in single layer films with a magnetic phase coexistence state of FM and AF phases, which may be exploited as a very simple structure for spin-valve devices. [ABSTRACT FROM AUTHOR]

Various types of anomalies of inverse dc susceptibility (H/M) have been observed in spin-chain compounds Ca3Co2-xMnxO6. For x = 1.0, the H/M curve exhibits a field-dependent downturn from the paramagnetic Curie-Weiss behavior, signaling the presence of a Griffiths-like cluster phase. A slight decrease of x leads to a rapid suppression of the Griffiths-like singularity, followed by an appearance of field-independent, non-Griffiths-like behavior at x = 0.92. This feature persists until x = 0.33, at and below which the H/M curve presents an unambiguous, field-independent upturn from the Curie-Weiss law. These Mn-doping-dependent anomalies of H/M curves are associated with complex competing magnetic interactions. [ABSTRACT FROM AUTHOR]