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• Dependence of the parameters of the ferromagnet S= 1 on temperature and anisotropy constant. • Temperatures of transitions to the paramagnetic and nematic phases were determined. • Temperature dependence of excitation spectra in the ferromagnetic and nematic phases. In the mean-field approximation, the influence of both temperature and the value of the single-ion anisotropy constant of the "easy axis" type on the phase states and excitation spectra of a non-Heisenberg ferromagnet with S = 1 is studied. The temperature dependences of the vector and tensor order parameters in both the ferromagnetic and nematic phases have been determined. The dependence of excitation spectra on temperature and the value of the anisotropy constant is studied. It is shown that at a temperature different from zero, an additional (non-relaxation) branch of excitations arises in both the ferromagnetic and nematic phases. The temperature dependence of the phase diagram is studied. [ABSTRACT FROM AUTHOR]

The magnetoresistance of superconducting Bi/Ni bilayers is investigated around the superconducting transition temperature. At temperatures within the superconducting transition, the magnetoresistance presents a superposition of symmetric peaks and hysteresis behaviors. The magnetoresistance peaks show the evidence of T C suppression due to stray fields from domain walls appearing during magnetization switching. The hysteresis behaviors show the effect of vortices motion on the superconductivity of Bi/Ni bilayers. This unusual magnetoresistance controlled by both stray fields and vortices provides a new understanding of the interaction between superconductivity and ferromagnetism in Bi/Ni bilayers. [ABSTRACT FROM AUTHOR]

The ground state properties along with thermodynamic and thermoelectric properties of quaternary CoFeCrAs alloy within the ordered LiMgPdSn-type structure have been investigated by employing first-principles calculations. The alloy offers half-metallic ferromagnet character with an indirect band gap of 1.12 eV in the minority spin state with total spin magnetic moment of 4µ B and follows Slater-Pauling relation. Effects on various properties of the material has been studied by the variation of the pressure and temperature. CoFeCrAs tenders large value of the Grüneisen parameter and small value for the thermal expansion coefficient. The materials present high Seebeck coefficient and huge power factor with the room temperature value of ∼−40 μV/K and 18 (10 14   μ Wcm −1  K −2  s −1 ) respectively, which make CoFeCrAs promising candidate for efficient thermoelectric material. [ABSTRACT FROM AUTHOR]

Systematic investigations were performed on the nature of the magnetic properties of Yb 14 MnSb 11 , which is the first ferromagnetic Kondo lattice compound in the underscreened limit and one of the highest thermoelectrically efficient materials with p -type conduction. The Rhode-Wohlfarth ratio (RWR) is estimated to be 1.01, which demonstrates the localized nature of the ferromagnetism in Yb 14 MnSb 11 , consistent with the predicted Ruderman–Kittel–Kasuya–Yosida (RKKY) like exchange interaction. Detailed analyses on critical behavior indicate a second-order ferromagnetic phase transition with critical exponents β = 0.307(2), γ = 0.923(9), and δ = 4.003(4), demonstrating a three-dimensional critical behavior with long-range interaction. Furthermore, the magnetocaloric effect and relative cooling power are estimated to be 0.772 J kg−1 K−1 and 16.43 J kg−1 at 5 T, respectively. The magnetic transition temperature of T C = 51.9(3) K is strictly estimated by evaluating the magnetic change of specific heat [ Δ C p (T , H) ]. The rare d -electron ferromagnetic Kondo lattice, small magnetocaloric effect, and high-temperature large thermoelectric efficiency making Yb 14 MnSb 11 to be a system of considerable interest. • The estimated Rhode-Wohlfarth ratio of 1.01 verifies a rare 3d electron localized ferromagnetism. • Detailed analyses on critical behavior indicate a three-dimensional critical behavior with long-range interaction. • Analyses on magnetic entropy change and relative cooling power demonstrate a small magnetocaloric effect. [ABSTRACT FROM AUTHOR]

Magnetization switching in ferromagnets has so far been limited to the current-induced spin–orbit–torque effects. Recent observation of helicity-independent all-optical magnetization switching (HI-AOS) in an exchange-coupled ferromagnet–ferrimagnet (FM-FEM) heterostructures expanded the range and applicability of such ultrafast heat-driven magnetization switching. Here we report the element-resolved HI-AOS dynamics of such an exchange-coupled system, using a modified microscopic three-temperature model. We have studied the effect of (i) the Curie temperature of the FM, (ii) FEM composition, (iii) the long-range Ruderman–Kittel–Kasuya–Yosida (RKKY) exchange-coupling strength, and (iv) the absorbed optical energy on the element-specific time-resolved magnetization dynamics. The phase-space of magnetization illustrates how the RKKY coupling strength and the absorbed optical energy influence the switching time. Our analysis demonstrates that the threshold switching energy depends on the composition of the FEM and the switching time depends on the Curie temperature of the FM as well as RKKY coupling strength. This simulation anticipates new insights into developing faster and more energy-efficient spintronics devices. • Simulation of ultrafast helicity-independent all-optical switching in exchange-coupled heterostructures. • Threshold switching energy depends on the composition of the ferrimagnet. • Switching of the ferromagnet gets faster with increasing T c and the RKKY exchange. [ABSTRACT FROM AUTHOR]

The magnetic properties of an unexpected superconducting bilayer consisting of non-superconducting Bi and ferromagnetic Ni have been investigated. A large magnetization signal is observed when the sample is cooled below the superconducting transition temperature in zero magnetic field, which has the same direction with the magnetization of the adjacent Ni layer. Interestingly, this Bi/Ni bilayer shows opposite responses to external magnetic field in zero field cooling (ZFC) process and field cooling (FC) process. It behaves diamagnetically in ZFC while paramagnetically in FC. Besides, magnetic hysteresis loops below the superconducting transition temperature show flux pinning and flux jumping effects. [ABSTRACT FROM AUTHOR]

This “Critical Focused Issue” presents a brief review of experiments and models which describe the origin of exchange bias in epitaxial or textured ferromagnetic/antiferromagnetic bilayers. Evidence is presented which clearly indicates that inner, uncompensated, pinned moments in the bulk of the antiferromagnet (AFM) play a very important role in setting the magnitude of the exchange bias. A critical evaluation of the extensive literature in the field indicates that it is useful to think of this bulk, pinned uncompensated moments as a new type of a ferromagnet which has a low total moment, an ordering temperature given by the AFM Néel temperature, with parallel aligned moments randomly distributed on the regular AFM lattice. [ABSTRACT FROM AUTHOR]

Static deformation of a ferromagnet under an action of ac magnetic field was observed and investigated in this work. The effect is due to even and nonlinear dependence of magnetostriction on magnetic field. It is shown that the deformation is proportional to the second derivative of magnetostriction over the field at low fields and depends on the static bias field. The deformation grows nearly linearly and then saturates with increasing ac field. For the samples with very different parameters like permendur and nickel the ac field induced static strain can reach ~50% of the saturation magnetostriction. [ABSTRACT FROM AUTHOR]

The different magnetic phases of the intermetallic compound Nd 5 Ge 3 are studied in terms of the specific heat, in a broad range of temperatures (350 mK–140 K) and magnetic fields (up to 40 kOe). The expected T 3 and T 3 / 2 terms are not found in the antiferromagnetic (AFM) and ferromagnetic (FM) phases respectively, but a gapped T 2 contribution that originates from a mixture of AFM and FM interactions in different dimensionalities under a large magnetocrystalline anisotropy, is present in both. An almost identical Schottky anomaly, that arises from the hyperfine splitting of the nuclear levels of the Nd 3+ ions, is observed in both phases, which leads us to state that the magnetic-field induced transition AFM → FM that the system experiments below 26 K consists in the flip of the magnetic moments of the Nd ions, conserving the average local moment. [ABSTRACT FROM AUTHOR]

The nonlinear localization phenomena in ferromagnetic spin lattices have attracted a steadily growing interest and their existence has been predicted in a wide range of physical settings. We investigate the onset of modulational instability of a plane wave in a discrete ferromagnetic spin chain with physically significant higher order dispersive octupole–dipole and dipole–dipole interactions. We derive the discrete nonlinear equation of motion with the aid of Holstein–Primakoff (H–P) transformation combined with Glauber's coherent state representation. We show that the discrete ferromagnetic spin dynamics is governed by an entirely new discrete NLS model with complex coefficients not reported so far. We report the study of modulational instability (MI) of the ferromagnetic chain with long range dispersive interactions both analytically in the frame work of linear stability analysis and numerically by means of molecular dynamics (MD) simulations. Our numerical simulations explore that the analytical predictions correctly describe the onset of instability. It is found that the presence of the various exchange and dispersive higher order interactions systematically favors the local gathering of excitations and thus supports the growth of high amplitude, long-lived discrete breather (DB) excitations. We analytically compute the strongly localized odd and even modes. Further, we employ the Jacobi elliptic function method to solve the nonlinear evolution equation and an exact propagating bubble-soliton solution is explored. [ABSTRACT FROM AUTHOR]

Random magnetic fields suppress the long-range magnetic ordering through the formation of the magnetic domains. The size of the domains is determined by the competition among the exchange interaction, the magnetic anisotropy, and the strength of the random field. Here we theoretically investigate the temperature dependence of the magnetization of the two-dimensional domains for the anisotropic Heisenberg model with a random magnetic field. We find that magnetization of the domains displays a first-order phase transition in which the magnetization is discontinuous at a critical temperature. Moreover, the first-order transition persists even in the presence of an external magnetic field whose magnitude is smaller than the strength of the disorder. The above unusual first-order phase transition can be experimentally tested with doped two-dimensional magnets. • A self-consistent RPA used to study the effect of random fields on 2D Heisenberg Model. • The system undergoes a first order phase transition instead of a second order. • A reduction in transition temperature scales with the strength of the random field. • First order phase transition persists if external field weaker than random field. [ABSTRACT FROM AUTHOR]

Possible approaches to creating a magnetoresistive memory with recording by electric field (MERAM) are considered. The memory based on a particular geometry of multiferroic BiFeO 3 is shown to be the most promising. The relatively small values of the weak ferromagnetic moment and linear magnetoelectric coupling constant in BiFeO 3 are not significant obstructions for creation of such a MERAM. The key factors are the coupling between electrical polarization and the antiferromagnetism vector in the multiferroic (not between polarization and magnetization vectors), as well as the exchange coupling between the antiferromagnetism vector and the ferromagnet layer magnetization caused by the spin-flop orientation of the latter two vectors at the interface. This is inherently an antiferromagnetic-ferroelectric device mechanism. [ABSTRACT FROM AUTHOR]

The ferromagnet–topological insulator–ferromagnet (FM–TI–FM) junction exhibits thermal and electrical quantum Hall effects. The generated Hall voltage and transverse temperature gradient can be controlled by the directions of magnetizations in the FM leads, which inspires the use of FM–TI–FM junctions as electrical and as heat switches in spintronic devices. Thermal and electrical Hall coefficients are calculated as functions of the magnetization directions in ferromagnets and the spin-relaxation time in TI. Both the Hall voltage and the transverse temperature gradient decrease but are not completely suppressed even at very short spin-relaxation times. The Hall coefficients turn out to be independent of the spin-relaxation time for symmetric configuration of FM leads. [ABSTRACT FROM AUTHOR]

The compound α-Fe 1.6 Ga 0.4 O 3 has been prepared by mechanical alloying and subsequent vacuum annealing at 800 °C. X-ray diffraction and Raman spectroscopy confirmed rhombohedral phase. The samples have shown enhanced ferromagnetic properties in comparison with α-Fe 2 O 3 sample. The samples also exhibited good signature of ferroelectric polarization. Increase of alloying time has affected the variation of ferromagnetic and ferroelectric parameters. The samples with 50 h alloying time showed relatively large leakage of polarization, where as the samples at lower and higher alloying time showed better ferroelectric properties. Details of the ferroelectric loop have been studied at different applied voltages and frequencies. It has been found that leakage of polarization can be optimized by adjusting the frequency of the applied voltage. The ferroelectric properties have been understood by correlating the observations of the dielectric properties (dielectric loss, dielectric constant, and electrical conductivity) of the samples. The results are interesting for understanding the mechanism of ferroelectric properties in non-traditional ferroelectrics. This work opens a wide scope for reviewing the ferroelectric and multiferroic properties in metal doped hematite system, which is structurally different from orthorhombic phase of GaFeO 3 that showed ferroelectric properties. [ABSTRACT FROM AUTHOR]

We theoretically study the proximity effect in the thin-film layered ferromagnet (F) – superconductor (S) heterostructures in F 1 F 2 S design. We consider the boundary value problem for the Usadel-like equations in the case of so-called “dirty” limit. The “latent” superconducting pairing interaction in F layers taken into account. The focus is on the recipe of experimental preparation the state with so-called solitary superconductivity. We also propose and discuss the model of the superconducting spin valve based on F 1 F 2 S trilayers in solitary superconductivity regime. [ABSTRACT FROM AUTHOR]

The magnetic and thermodynamic properties such as the magnetization, internal energy, specific heat and susceptibility of spin-2 Heisenberg ferromagnetic system on a square lattice are studied by using Green׳s function technique. Without including the next nearest neighbor interaction, one doesn׳t observe the second-order phase transitions. We found that only when the next nearest neighbor interaction is greater than the nearest neighbor interaction, the second-order phase transitions exist for the small single-ion anisotropy values. Indeed, in the case of negative anisotropy which corresponds to first-order phase transitions, the energies have discontinuities. At the same time, the specific heat shows two peaks. [ABSTRACT FROM AUTHOR]

A review of our recent results on the spin valve effect is presented. We have used a theoretically proposed spin switch design F1/F2/S comprising a ferromagnetic bilayer (F1/F2) as a ferromagnetic component, and an ordinary superconductor (S) as the second interface component. Based on it we have prepared and studied in detail a set of multilayers CoO x /Fe1/Cu/Fe2/S (S=In or Pb). In these heterostructures we have realized for the first time a full spin switch effect for the superconducting current, have observed its sign-changing oscillating behavior as a function of the Fe2-layer thickness and finally have obtained direct evidence for the long-range triplet superconductivity arising due to noncollinearity of the magnetizations of the Fe1 and Fe2 layers. [ABSTRACT FROM AUTHOR]

Abstract: In this study, 3D finite element analysis is presented by calculating the residual magnetic field signals of ferromagnets under the plastic deformation. The contour maps of tangential and normal RMF gradients are given, and the 3D effect is discussed. The results show that the tangential peak–peak amplitude and normal peak–vale amplitude are remarkably different in 2D and 3D simulations, but the tangential peak–peak width and normal peak–vale width are similar. Moreover, some key points are capable of capturing the plastic-zone shape, especially when the lift-off is small enough. The present study suggests an effective defect identification method with Metal magnetic memory (MMM) technique. [Copyright &y& Elsevier]

Abstract: Ferromagnet is a major source of disturbance to magnetic sensor. An improved method positioning the compensation coils beside the ferromagnet is presented for disturbance compensation. The method does not ignore the distance between ferromagnet and coils, and considers the non-orthogonality of the coils. The simulation results show that the compensation precision exceeds 96% though the noise amplitude of compensation current reaches 10mA. In contrast, precision of the method without consideration of the distance does not exceed 90%. [Copyright &y& Elsevier]

Abstract: In an easy-axis ferromagnet, the effect of superposition of severe plastic deformation by twisting (SPDT) perpendicular to the “easy axis” on the ferromagnetic order parameter (OP) distribution is studied. The consideration is carried out within the frameworks of phenomenological theory of Landau. It is shown that SPDT effects the results in occurrence of the normal component of the magnetic OP and periodical change of OP modulus. The law of distribution of the magnetic moment is determined by proximity of the temperature of the crystal and any phase transition. [Copyright &y& Elsevier]

Abstract: A systematic study of Ge substitution in Ru2FeSi alloys synthesized by the arc melting method is presented in this work. Crystallographic analysis using the Rietveld refinement technique reveals that at room temperature, all compositions of Ru2Fe(Si1−x Ge x ) alloys with 0≤x≤1mol%, exhibit cubic B2 structure with unit cell volume increasing from 203.3 to 212.8Å3 as x was increased from 0 to 1mol%. B2 structure occurs in Heusler (X2YZ) compounds due to partial disorder in the Y and Z sites. Magnetization measurements showed that Ru2FeSi is antiferromagnetic with Neel temperature of 270K. Substitution of Ge in Si sites resulted in the development of ferromagnetism as indicated by magnetization and magnetic susceptibility data collected on the samples. Curie temperature increased from 354K to 460K as x was increased from 0.25 to 1.00mol%, which shows that the ferromagnetic state becomes dominant as x is increased in the quaternary alloys. [Copyright &y& Elsevier]

Abstract: Inelastic neutron scattering experiments were performed on an intermetallic compound, MnP. We used a newly developed High Resolution Chopper Spectrometer, HRC, for energy transfers , besides various triple axis spectrometers; LTAS for energy transfers , TOPAN for and TAS-1 for . Spin wave excitations were observed in the ferromagnetic phase of MnP in the entire Brillouin zone along the a ⁎- and b ⁎-axes. The zone boundary energies of spin waves were determined to be around 60meV along the a ⁎-axis and around 75meV along the b ⁎-axis, and the dispersion relations showed two branches for both axes. The observed dispersion relations of spin waves were well described by an isotropic Heisenberg interaction adding a single ion anisotropy with two sub-lattices. [Copyright &y& Elsevier]

Abstract: Polycrystalline Tb1−x Dy x MnO3 (x=0.0, 0.3, 0.5, 0.6, and 0.8) were prepared by the traditional solid-phase reaction method. The XRD result shows that Tb0.4Dy0.6MnO3 may have a different structure; it has two diffraction peaks near 33.30° while other samples have three diffraction peaks at the same diffraction angle. The magnetic properties of Tb0.4Dy0.6MnO3 are also different from those of the other samples. An exchange-bias effect was observed at 5K with the field cooling of ±5T for Tb0.4Dy0.6MnO3. The dc and ac magnetizations as well as magnetic hysteresis measurements suggest the coexistence of antiferromagnet and ferromagnet characteristics which originate from the interplay of 3d and 4f electrons at the rare-earth sublattice and low temperature in Tb0.4Dy0.6MnO3. [Copyright &y& Elsevier]

Abstract: The perovskite manganite systems have been the materials of tremendous interest due to their strong correlation between structure, transport and magnetism. These materials in their single-crystal form show colossal magneto-resistance (CMR), but the applied fields are very high (∼1–5T). The polycrystalline samples do show high low-field magneto-resistance (LFMR), but good amount of control over particle sizes and grain-boundary distribution is required, which is well known but less realized in practical approaches. In this context, we report on synthesis and manipulation of polycrystalline La0.7Ba0.3MnO3 (LBMO) submicron powders using citric acid chelation. The Citrate-gel route is used to synthesize poly-dispersed LBMO powders which are subjected to citrate chelation for a duration of 0 (LB0) to 4h(LB4) . The samples show improved ordering in X-ray diffraction patterns. Raman spectroscopy scans indicate changed mode signatures due to the probable chelating process, which alters the surface morphology. X-ray photoelectron microscopy shows an evidence of fine citrate layer on the grain boundaries. Low temperature B–H curves exhibit fine hysteresis loops for all samples, while room temperature B–H curves shows paramagnetic response. Scanning electron microscopy images showed the formation of well arranged, connected, mono-dispersed grains of LB4 sample, as against polydispered LB0. The magneto-resistance (at H=100kOe) is seen to enhance for LB4 at its transition temperature (75%, as compared to LB0, where it is 60%), which can be attributed to the well-controlled inter-grain tunneling phenomenon and thin insulating regions in between, created due to citrate chelation, which probably enhances the scattering phenomenon and its susceptibility to applied fields. As citric acid is known to chelate Mn ions, it probably chelates the smaller LB particulate structure and leaves behind citrate-connected submicron grains of LBMO, which are seen to be well engineered. [Copyright &y& Elsevier]

Abstract: Behavior of spin-wave propagation in ferromagnetic medium with non-uniform distribution of magnetic parameters is studied. In particular, the influence of external magnetic field, spin-wave frequency and exchange parameter on behavior of surface spin-wave propagating through inhomogeneity made in form of lens (lens is biaxial ferromagnet placed into uniaxial ferromagnetic medium) is studied. [Copyright &y& Elsevier]

Abstract: Based on extensive Mossbauer effect (ME) and magnetization measurements, the orthorhombic AlFe2B2 was characterized as a ferromagnet (FM) because this character is evident as an onset of a FM transition at T c =320K and characteristic magnetizations isotherms below T c . At liquid helium temperatures, the magnetization saturates to per Fe atom; a value which is half the one reported for the iron metal indicating a relatively more filled 3d band. The ME analysis revealed a hyperfine field H(0) of 88(2)kOe, an isomer shift (relative to Fe) of 0.50(2)mm/s, and a quadrupole parameter of 0.02mm/s: all parameters extrapolated to zero Kelvin. The itinerant character of the magnetic moment will be discussed. [Copyright &y& Elsevier]

Abstract: We present experimental evidences for magnetization modification by superconductivity in a series of Nb/Ni80Fe20/Nb trilayers. By monitoring the magnetization in a zero field as a function of temperature, we observed an irreversibility in magnetization between the cooling and warming branches just above the superconducting transition temperature Tc . These results suggest that the magnetization of the ferromagnetic Ni80Fe20 layer is reduced by the mutual interactions between the ferromagnet and superconductor. Moreover, this effect diminishes with increasing thickness of the Ni80Fe20 layer, which indicates that the interaction between the superconducting and magnetic layers occurs mainly at the vicinity of the interfaces. [Copyright &y& Elsevier]

Abstract: The thickness–roughness phase diagram of a thin ferromagnetic film on an antiferromagnetic substrate is studied in the case where the roughness of the interface between the layers causes frustration of the exchange interaction between them. It is shown that the account of single-ion anisotropy makes the phase diagram significantly more complicated in comparison with that calculated within the exchange approximation. The evolution of a new type of domain walls caused by frustrations is traced with an increase in the film thickness and the width of the atomic steps on the film–substrate interface. [Copyright &y& Elsevier]

[Display omitted] • Ru 2 FeSi 1- x Ge x alloys transform from antiferro-ferromagnetic for x > 0.15. • ab initio study of magnetic interactions in Ru 2 FeSi 1- x Ge x alloys. • B2 disorder favours antiferromagnetic interaction over ferromagnetic. • DOS at E F of L 2 1 and B 2 show non-half-metallic nature. X-ray diffraction studies on arc melted Ru 2 Fe(Si 1-x Ge x) (0 ≤ x ≤ 1) alloys did not show the characteristic (1 1 1) and (2 0 0) super-lattice peaks of the stable L2 1 structure of full Heusler alloys. The alloy with x = 0 exhibited antiferromagnetic behaviour. However, with increase in x, the alloys became ferromagnetic. In order to understand the origin of the novel magnetic behavior of these alloys and its correlation with their crystal structure, ab initio study was carried out using spin-polarized relativistic Korringa-Kohn-Rostoker Green's function method. The study shows that the antiferomagnetism in the alloy with x = 0 is due to the presence of B2 disorder. Due to this, the 2nd nearest neighbour (NN) exchange interaction between the Fe atoms at proper and improper sites, respectively, becomes strongly antiferromagnetic which dominates over the 1st NN ferromagnetic exchange interaction. With increase in x, the alloys become ferromagnetic with an improvement in L 2 1 ordering which in turn makes the 1st NN interaction strongly ferromagnetic. The electronic structure calculations show no half metallic gap in either spin direction for all the alloys. Comparison of experimental and theoretically estimated properties of Ru 2 Fe(Si 1-x Ge x) alloys provides insight to the variation in the magnetic interaction with the composition and the disorder present in the alloys. [ABSTRACT FROM AUTHOR]

• FeWGa half-Heusler compound is nearly half-metal ferromagnets. • The total magnetic moments are 1.005, 0.876 and 2.852 μ B /f.u. for Type I, Type II and Type III, respectively. • The Debye temperatures were obtained as 200.83 K, 396.11 K and 320.34 K for Type I, Type II and Type III, respectively. • The Curie temperature of FeWGa compound is 541.29 K. The structural, electronical, elastical, Debye temperatures and magnetic calculations of the FeWGa half-Heusler compounds were calculated for Type I, Type II and Type III phases by using WIEN2k. The ferromagnetic state of Type II phase is energetically more stable than types. The band gaps were obtained only in Type II phase when GGA and TB_mBJ methods were used. The total magnetic moments were calculated as 1.005, 0.876, and 2.852 μ B /f.u. for Type I, Type II and Type III, respectively. However, when TB_mBJ method was used, the total magnetic moment of Type II phase was obtained as 1.00 μ B /f.u., which was compatible with Slater-Pauling rule. According to the elastically calculations, Type II and Type III phases are stable, anisotropic and ductile, while Type I phase is unstable against deformation. Then the Debye temperatures were obtained as 200.83 K, 396.11 K, and 320.34 K for Type I, Type II and Type III, respectively. The FeWGa compound has 541.29 K and 396.11 K Curie and Debye temperatures, respectively. Therefore, it is an ideal compound that can be used in spintronic applications. [ABSTRACT FROM AUTHOR]

• Spin-wave can be self-focused by a pulsed flat-top excitation. • Focusing effect can be enhanced due to a spin wave reflection by domain walls. • A pulsed flat-top excitation can be an efficient way to create magnetic droplets. We investigate a spin-wave (SW) self-focusing in a ferromagnetic FePd thin film with a perpendicular magnetic anisotropy by using micro-magnetic simulation. In a one-dimensional structure, a point-excitation of forward volume magnetostatic waves leads the SW propagation in the form of a wave packet. When SWs are excited over a wide area with a uniform amplitude distribution, the SW propagation occurs by taking not only a diverging component but also a focusing-like component. Interestingly, we can increase the focusing effect by reflecting the diverging waves at the magnetic phase boundary, such as domain walls. This SW focusing appears also in a two-dimensional system, and, furthermore, magnetic droplets can be easily formed at the focal points when the focused SW intensity exceeds an appropriate threshold. Based on these results, we can propose the flat-top excitation of the magnetostatic waves as an efficient way to generate the SW self-focusing and also to create magnetic droplets in a multi-domain state of perpendicularly magnetized systems. [ABSTRACT FROM AUTHOR]

The spin–glass behavior in the ferromagnetic phase of Tm 2 Cu 2 In was investigated by dc–, ac–magnetization, and non-equilibrium dynamics characterizations. An argon arc–melted polycrystalline sample of the compound of Tm 2 Cu 2 In was found to adopt the Mo 2 FeB 2 –type tetragonal structure (space group P 4 / m b m). The temperature variation of dc–magnetization exhibits a ferromagnetic behavior with Curie temperature T C = 32.5 K. The zero field cooled (ZFC) and field cooled (FC) magnetic curves show the thermomagnetic irreversible behavior below T C. The field dependence of irreversible temperature follows the Almeida–Thouless line. The frequency and ac–driven field dependent anomalies in ac–susceptibility results indicate the existence of a spin–glass state in Tm 2 Cu 2 In. The time dependence of magnetization further supports the spin–glass behavior observed in Tm 2 Cu 2 In. The frequency dependence of the freezing temperature in the real part of ac–susceptibility has been analyzed on the basis of a power–law divergence and Vogel–Fulcher law. The obtained results reveal that Tm 2 Cu 2 In belongs to the ferromagnetic canonical spin–glass class of compounds. • Tm 2 Cu 2 In was synthesized using an arc-melting system. • Magnetic studies confirm the presence of spin–glass behavior in Tm 2 Cu 2 In. • Tm 2 Cu 2 In shows spin glass order at a temperature of 31.1 K. [ABSTRACT FROM AUTHOR]

Abstract: The density-functional theory (DFT) within the full potential linearized augmented plane wave (FPLAPW) method was applied to study the layered organic–inorganic hybrid Fe[CH3(CH2)2PO3(H2O)]. The relative stability of the ground state, the electronic band structure, the magnetic and the conducting properties were investigated. The calculations reveal that the compound has a stable ferromagnetic ground state and the spin magnetic moment per molecule is about 4.0 μ B, which is mainly from Fe(II) ion. By analysis of the band structure, we find that the compound has half-metallic properties. [Copyright &y& Elsevier]

Abstract: Detailed structural and magnetic characterization was carried out on nominally amorphous melt-spun ribbon based on the composition Nd60Fe30− x Al10+ x to pursue the origins of its anomalously large coercivity values. The combined structural and magnetic analyses point to the existence of antiferromagnetic motes within the melt-spun ribbon. The average diameter of these motes is 1.2±0.5nm and their crystal structure is related to the Nd6Fe13− x Al1+ x , δ-phase structure, which under equilibrium conditions is the primary solidification phase near the Nd60Fe30Al10 composition. These motes are hypothesized to strongly couple to the ferromagnetic matrix phase in an “exchange-bias”-type manner and confer extremely high values of coercivity at low temperature. The composition dependence of the δ-phase Néel temperature is reflected in the composition dependence of the onset of large values of coercivity in the melt spun ribbons. The results obtained from melt-spun ribbons are compared to those obtained from a 10gm drop-cast ingot 6mm diameter of the same nominal composition and are found to be internally consistent. Delineation of the solidification pathway in the vicinity of the composition RE60Fe30Al10 provides a sound physical explanation of the variety of microstructures and associated variety of magnetic behavior found in cast and melt-spun forms of this material. [Copyright &y& Elsevier]

Abstract: Exchange biasing is studied in Co80Cr20 (CoCr)/FeMn bilayers with a ferromagnetic material granular CoCr. Unique exchange biasing characteristics closely related to the microstructures and magnetization reversal process of granular CoCr have been observed. Although the exchange field in CoCr/FeMn bilayers is inversely proportional to the CoCr layer thickness, similar to the conventional ferromagnet/antiferromagnet bilayers, the coercivity is found to increase with increasing CoCr layer thickness. More importantly, of the CoCr/FeMn bilayers is smaller than that of CoCr single layer films. [Copyright &y& Elsevier]

Abstract: For permalloy/CoO multilayers, the exchange field and the coercivity of the perpendicular and longitudinal exchange biasing have been found to decrease with increasing temperature. After zero field cooling, perpendicular magnetic anisotropy is observed. For small permalloy layer thickness, perpendicular anisotropy film can be established at low temperatures. [Copyright &y& Elsevier]

Some exact dynamic and static solutions of Landau–Lifshitz equations in antiferromagnets and ferromagnets found in this work. These solutions can be used for describing distribution of order parameter in small magnetic particles. [Copyright &y& Elsevier]

The magnetic phase diagram of the nearly 2D ferromagnet (CH3NH3)2CuCl4 (TC=8.85 K) in magnetic fields applied perpendicular to the easy axis is obtained. In this system, the ferromagnetic moments lie in planes (ab planes) formed by the Cu atoms and point along the a crystallographic direction. For field applied along b-axis (intermediate anisotropy axis), a second-order transition to the paramagnetic phase occurs at the field of 80 Oe at the lowest measured temperature (T=1.8 K). When the field is applied in a direction perpendicular to the Cu planes (c-axis) the paramagnetic phase is reached only above 1500 Oe after a double transition. The first transition (∼500 Oe) is suggested to be an order–order transition in which a spin reorientation occurs. The obtained in-plane and out-of-plane anisotropy are HAin=80 and HAout=1500 Oe, respectively. [Copyright &y& Elsevier]

The temperature dependence of the AC susceptibility (χ) at constant applied magnetic field was investigated in the paramagnetic region close to the ferromagnetic transition in MnP. Above the curie temperature (Tc=291.9 K), a maximum in the χ(T,H) curves was observed at Tm(H). The temperature of the maximum increases with increasing the applied field. The behavior of Tm(H) is governed by the gap exponent of the scaling function (Δ=γ+β). From the fitting of our data we found that Δ=1.51±0.03 which is in excellent agreement with the theoretical predictions that are in the range 1.49<Δ<1.56. [Copyright &y& Elsevier]

• A polycrystalline compound Tb 2 Rh 3 Ge has been prepared by arc-melting. • Crystal structure and magnetic properties of Tb 2 Rh 3 Ge have been studied. • Tb 2 Rh 3 Ge shows a second-order ferromagnetic–paramagnetic phase transition. • Magnetocaloric effect of Tb 2 Rh 3 Ge has been studied from isothermal magnetization. We report the structural, and magnetic properties as well as magnetocaloric effect of a polycrystalline compound of Tb 2 Rh 3 Ge. This compound crystallizes with Mg 2 Ni 3 Si -type of rhombohedral Laves phases (space group R 3 ‾ m , hR18). The magnetic properties and magnetocaloric effect of Tb 2 Rh 3 Ge are explored through dc-magnetization measurements. Temperature dependence of magnetization revealed that the compound exhibits ferromagnetic behavior with T C = 56 K. The field dependence of magnetization indicates that Tb 2 Rh 3 Ge is a soft ferromagnet. The obtained isothermal magnetic entropy changes (Δ S m ) and refrigeration capacity (relative cooling power) for a change of magnetic field 0–9 T are 12.74 J kg−1K−1 and 497(680) J/kg respectively. The Arrott plots and universal curve of normalized Δ S m indicate that this compound undergoes a second order ferromagnetic phase transition. [ABSTRACT FROM AUTHOR]

• In ferromagnets, a caustic of magnetoelastic waves arises. • The direction of the caustic is controlled by the frequency of magnetoelastic waves. • The difference between the internal and external magnetic fields produces a caustic. The caustic of magnetoelastic waves (MEW) propagating in thick-film ferromagnets is investigated. The model of continuous medium is employed, and MEW are considered in the long wavelength approximation. It is shown that in thick-film samples the difference between the internal and external magnetic fields leads to a special form of the anisotropy of the MEW spectrum and, accordingly, to the appearance of a caustic. The possibility to control this phenomenon with the frequency of MEW is revealed. In particular, the directions and frequency ranges of the waves where the caustic occurs are obtained. [ABSTRACT FROM AUTHOR]

Abstract: Small angle neutron scattering (SANS) measurement has been performed on the reentrant ferromagnet Cr60Fe20Mn20 alloy. An increase in the SANS intensity is observed below 100K coinciding with an increase in the magnetization. It exhibits a maximum at 40K and shifts to lower temperatures with increase in Q. The magnetic part of the SANS intensity fits to a Lorentzian at all temperatures. The temperature dependence of the inverse correlation length exhibits a minimum at 40K. In the antiferromagnetic spin-glass phase at 15K ferromagnetic correlations of ~40Å is observed. [Copyright &y& Elsevier]

Abstract: We study the 0– transition by taking into account magnetic scattering in a dirty ferromagnet (FM). Using the fourth order perturbation theory for the tunneling Hamiltonian and Green''s function method, we formulate the Josephson effect in a SC/FM/SC junction, where SC is a superconductor. It is found that Josephson critical current shows the damped oscillation as a function of the thickness of the ferromagnet and the 0– transition occurs. Moreover, it is found that the 0– transition occurs by changing temperature due to the magnetic scattering. [Copyright &y& Elsevier]

Abstract: Spin waves in arrays of interacting ferromagnetic nanowires are studied theoretically using a microscopic Hamiltonian-based approach. The dependence of these modes on a magnetic field applied transverse to the wires and on the spacing between wires are investigated. Numerical results are presented for a hexagonal array of seven nickel nanowires, showing that the spin waves exhibit strong coupling with mode splitting and band effects as the interwire spacing is reduced. [Copyright &y& Elsevier]

Abstract: Magnetostatic mode calculations are presented for the bulk and surface modes in long cylindrical magnetic nanorings with arbitrary values of the inner and outer radii. Numerical examples for the dispersion relations are presented for the cases of the ferromagnet Ni and the uniaxial antiferromagnet GdAlO3. The generalization to include retardation effects and hence magnetic polaritons in a ring is briefly indicated. [Copyright &y& Elsevier]

Abstract: The magnetic resistivity is restudied theoretically for ferromagnetic metals, which are assumed to have spins localized at magnetic ions and carriers of low density. It is shown that the half-metallic state realized under nonzero magnetizations exhibits low ''s, while is extraordinary enhanced near because of the smallness of the Fermi surface. The obtained gives the characteristics of the colossal magnetoresistance observed. [Copyright &y& Elsevier]

Abstract: We succeeded in growing a single crystal of with the tetragonal crystal structure by the Sn-flux method and measured the temperature dependence of electrical resistivity, magnetization and magnetic susceptibility. orders ferromagnetically below . The magnetic properties are highly anisotropic. An easy-axis of the magnetization is found to be the [0 0 1] direction (-axis), while the [1 0 0] direction (-axis) corresponds to the hard-axis in magnetization, indicating Ising-type ferromagnetism. The saturation moment is determined as /U. [Copyright &y& Elsevier]

• The total magnetic moments are 2.00, 4.00, 4.00 and 2.00 µ B /f.u. • The band gap values are 0.697, 0.773, 0.706 and 0.819 eV. • Co 2 ReSb, MnCoReSb, CoMnReSb and Mn 2 ReSb compounds are elastically stable and ductile materials. One of the fields spintronics is dealt with nanoelectronic devices that reduce power consumption and increase memory with the help of spin polarized electrons. Therefore, both half-metal ferromagnet materials and non-magnetic materials created by spin injection from half-metal ferromagnets can also be used in spintronic applications. We wondered whether Co 2 ReSb, MnCoReSb, CoMnReSb and Mn 2 ReSb compounds that have not been studied experimentally and theoretically are suitable materials for use in spintronic applications. The half-metal ferromagnetic predictions of compounds were investigated by using Wien2k programme in Tran Blaha modified Becke-Johnson (TB_mBJ) method. First, the volume-energy optimization curves were plotted and observed that FM phases were the most stable energetically. Then the total magnetic moments of Co 2 ReSb and Mn 2 ReSb compounds were obtained as 2.00 µ B /f.u. while these were 4.00 µ B /f.u. in MnCoReSb and CoMnReSb compounds. Finally, the elastical studies showed that each compound was elastically stable because the stability conditions were satisfied. Therefore, Co 2 ReSb, MnCoReSb, CoMnReSb and Mn 2 ReSb compounds are half-metal ferromagnetic materials and they can be new candidates for using in spintronic applications. [ABSTRACT FROM AUTHOR]

• The polycrystalline samples of Fe 2 MnSn were synthesized by arc-melting. • Contrary to ab-initio calculation Fe 2 MnSn reveals a hexagonal DO 19 structure. • The Curie temperature is T C = 586(10) K and the saturation magnetization reaches 5.87 μ B /f.u. • Electrical resistivity reveals no signs of half-metallic behavior predicted theoretically. • The MOKE spectra suggests the main influence of a low energy inter-band transition pointing to the loss of half-metallicity. Fe 2 MnSn compound was prepared in the form of polycrystalline ingot by arc-melting. In contrast to the theoretical predictions of stable tetragonal Heusler compound, the material crystallizes in a hexagonal DO 19 crystal structure and orders ferromagnetically below T C = 586(10) K that is only about half of the calculated value of 1012 K. Magnetic moment 5.87 μ B at 10 K is less or about in line with various theoretical predictions. However, electrical resistivity and optical studies reveal no signs of half-metallic behavior predicted theoretically. The change in the slope of the MOKE spectra below 1.5 eV suggests the main influence of a low energy inter-band transition which points to the loss of half-metallicity in agreement with resistivity and optical measurements. [ABSTRACT FROM AUTHOR]

• Critical behaviour of intermetallic Gd 2 Rh 3 Ge has been studied from isothermal magnetization. • The value of critical exponents β , γ and δ are determined. • The exchange interaction J (r) is found to decay as r - 4.91 in the system. The critical behavior of a new ternary intermetallic compound Gd 2 Rh 3 Ge has been investigated around the second order ferromagnetic transition temperature ( T C ). The field dependence of magnetic entropy changes and isothermal magnetization at critical temperature were used to study critical behavior in Gd 2 Rh 3 Ge. The exponents β = 0.299(2) and γ = 1.042(1) were evaluated from the modified Arrott-plot method, while β = 0.308(1) and γ = 0.982(2) were estimated through the Kouvel-Fisher method. The reliability of the obtained critical exponents were examined by using the universal scaling hypothesis. These estimated values for the critical exponents indicate that the ferromagnetic compound Gd 2 Rh 3 Ge has long-range interactions between spins, which decays with distance (r) as J(r) ∼ r - (σ + d) with σ = 1.91. [ABSTRACT FROM AUTHOR]