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Abstract: We present a detailed specific heat analysis of the non-magnetic R 2RhIn8 (R=Y, La, Lu) compounds, crystallizing in the tetragonal Ho2CoGa8-type structure. We focus on the lattice contribution and analyze the characteristic parameters in the Debye and Einstein models. The most prominent feature is the presence of low energy phonons in these compounds. We also give details about the single crystal preparation and structural parameters. First-principles electronic-structure calculations based on density-functional theory have been performed and compared with available experimental structural and electronic data. [Copyright &y& Elsevier]

Abstract: A two-ion model for rare-earth antiferromagnets was employed in the present work to study the magnetic and thermodynamic properties of ErNi2B2C, and derive an analytic formula for the Néel temperature of the compound with the quantum perturbation theory. To apply the theory, four new base functions had to be composed due to the special forms of its crystal-field (CF) wavefunctions. Our theoretical analysis suggested that the magnetic behavior of the compound be governed by these low-lying CF levels in the temperature region at least up to 100K. [Copyright &y& Elsevier]

Abstract: We report our theoretical studies on the magnetic and thermodynamic properties of DyFe2Si2 using the crystal-field parameters (CFPs) proposed by Chatterji et al. recently . Our calculated magnetization and magnetic specific heat curves obtained with the above CFPs based on the two-ion model we developed recently show reasonable agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Abstract: We present the results of XRD, magnetization, resistivity and specific heat measurements of CeIr2Si2 single crystals for both, the low-temperature α-phase and the high-temperature β-phase, respectively. The α-phase adopts the tetragonal ThCr2Si2-type whereas the β-phase forms in the CaBe2Ge2-type structure. Both the phases remain paramagnetic down to low temperatures, nevertheless both, the magnetization and resistivity exhibit pronounced anisotropy in the whole temperature range of measurements (2–300K). Results of fitting the temperature dependence of the susceptibility within the interconfiguration-fluctuation model point to the Ce valence fluctuating between 3+ and 4+. The α-phase behaves as a Fermi-liquid (FL) at low temperatures whereas the β-phase exhibits non-Fermi-liquid (NFL) features. The results are discussed in context of other similar polymorphic compounds. [Copyright &y& Elsevier]

Abstract: The magnetization (magnetic susceptibility), specific heat and electrical resistivity of a PrRhIn5 single crystal were studied. Van Vleck-type paramagnetic behavior and strong magnetocrystalline anisotropy were observed, which is attributed to a strong crystal-field effect on the Pr3+ ion. A crystal-field effect on the electrical resistivity was observed as well. We focused on the measurement of the specific heat down to low temperatures (down to 0.4K) in different magnetic fields. Indications of a field-induced transition to the quadrupolar ordered state below 0.4K were found in the specific-heat data in magnetic fields. First-principles calculations based on density functional theory of the electronic structure and crystal-field interaction were performed in order to better understand the experimental findings. [Copyright &y& Elsevier]

Abstract: A NdRhSn single crystal has been grown and investigated with respect to crystal structure and magnetic behavior. The hexagonal ZrNiAl-type crystal structure has been confirmed by the X-ray diffraction analysis. The magnetization and specific heat were measured as functions of temperature and magnetic field applied along the crystallographic a- and c-axes, Strong uniaxial magnetocrystalline anisotropy was observed with the c-axis as easy magnetization direction. Analysis of experimental data leads to the following scenario of magnetism in NdRhSn: The compound is paramagnetic at high temperatures. At 9.8K, a transition from the paramagnetic state to antiferromagnetic (AF) ordering of the Nd magnetic moments takes place. The temperature interval of the AF-phase stability is narrow and, at 7.6K, the magnetic moments in the compound condense to a ground state characterized by a spontaneous magnetization corresponding to about 2/3 of the value of the Nd3+ free-ion moment. This may be either due to crystal-field effects or to a complex magnetic structure. The results of ab initio calculations of the NdRhSn electronic structure confirmed that besides the stable Nd magnetic moment due the localized 4f-electrons only a very small magnetic moment of at most 0.1μB is induced at the Rh site due to the polarized Rh 4d-electron states hybridizing with the Nd 5d-electron states, i.e. the Rh moment plays only minor role in the total balance of the magnetic moments in this compound. [Copyright &y& Elsevier]

• Magnetic susceptibility and specific heat of polycrystalline Dy2Ir2O7 are analysed within the frame of mean field approximation considering model of crystal field and Zeeman interaction. • The Ir-Ir correlations are captured as bifurcation of ZFC/FC magnetic susceptibilities at 128 K and anomaly in specific heat at respective temperature. • The deviation from mean-field behaviour of Dy ions is deduced from the magnetic susceptibility and also isothermal magnetization data, where the calculations cannot explain the magnetic behaviour already well above the temperature of Dy-Dy correlations (1 K). • The anomaly in magnetic contribution to specific heat was identified at 20 K indicating the possible presence of strong Ir-Dy correlations. The magnetic properties of pyrochlore iridate Dy 2 Ir 2 O 7 prepared by CsCl flux method were investigated by means of heat capacity and magnetization measurements. The low temperature behaviour was confirmed to be consistent with previously published results, whereas the high temperature data and their analysis are presented for the first time. The bifurcation of zero field-cooled and field-cooled magnetization curves coincides well with the onset of the anomaly in specific heat pointing to an ordering of the iridium sublattice. We confront the previously determined Dy3+ CF scheme with our high-temperature magnetization and specific heat data. The difference between calculations and experimental data, represented by 20 K specific heat anomaly, suggests the behaviour beyond the mean field approximation. The Dy 2 Ir 2 O 7 differs from the rest of the heavy rare-earth pyrochlore iridates, where the mean field approximation constitutes an adequate description. The deeper understanding of the Dy 2 Ir 2 O 7 magnetic behaviour requires, among others, also the phonon spectra studies. [ABSTRACT FROM AUTHOR]

Our study is focused on superconductivity in LaPt 2 Al 2 compound. Specific heat and electrical resistivity measurements reveal a superconducting state below 0.57 K. Superconducting behaviour is in agreement with the weak coupling limit of BCS theory. The electronic Sommerfeld coefficient and equilibrium volume were described by first principles methods. The calculated electron phonon constant, λ = 0.48 , using the McMillan formula is small. The crystal lattice of LaPt 2 Al 2 is described by the orthorhombic space group C m m e. Polarisation contrast microscopy reveals a domain structure, which is the result of a symmetry lowering structural transition above room temperature. • The superconducting state was found in LaPt 2 Al 2 below 0.57 K. • The superconducting behaviour is in agreement with Bardeen–Cooper–Schrieffer theory. • The domain structure suggests structural transition above the room temperature. [ABSTRACT FROM AUTHOR]

A Ce 2 Pd 2 In single crystal was synthesized employing the Czochralski growth method from a stoichiometric melt. It was found to crystallize in the tetragonal Mo 2 FeB 2 -type structure. The investigation by means of X-ray diffraction, magnetization, specific heat, and electrical resistivity measurements revealed two successive magnetic phase transitions at around 4.5 and 4.1 K in the possibly slightly off-stoichiometric (Pd rich) crystal. Ferromagnetic ground state changes into the paramagnetic state through an intermediate antiferromagnetic phase. The measured magnetization and specific heat data were discussed in the view of first principles calculations of crystal field for Ce 2 Pd 2 In. Uniaxial magnetic anisotropy confining Ce moments into the c -axis has rather high energy exceeding 5 meV. Full ordered Ce-4 f 1 moments 2.14 μ B do not indicate any Kondo-type interaction, no many body enhancement of the Sommerfeld coefficient can be deduced. [ABSTRACT FROM AUTHOR]

In this work, we report results of specific heat and magnetization measurements on a single crystal of Nd 2 IrIn 8 . The compound orders antiferromagnetically below the Néel temperature of 12.5(2) K. Nd 2 IrIn 8 exhibits magnetic anisotropy with c as the easy axis. Two sharp metamagnetic transitions are present at 2 K. The measured data have been used to construct the low-temperature phase diagram for H || c . The measured susceptibilities and specific heat are compared to results based on first-principles calculations of the crystal-field parameters. [ABSTRACT FROM AUTHOR]

Abstract: We have developed a new quantum Monte Carlo approach and utilized it to calculate the magnetic structure, magnetization, and specific heat, etc., of nanoparticles composed of 3d magnetic ions. For comparison, we also performed simulations with the self-consistent computational algorithm which we proposed recently. The calculated results obtained with the two methods are identical, verifying their correctness. We also found that the combination of the two above algorithms can improve the computational efficiency considerably and have more general applicability. [Copyright &y& Elsevier]

• A bifurcation of ZFC and FC magnetization data is observed below 140 K. • It mirrors as a broad anomaly in the temperature development of specific heat. • Short-range correlations between Ir magnetic moments, rather than long-range order of Ir sublattice. • A strong frequency dependence of ac-susceptibility, a paradigmatic sign of a spin-glass transition. • Relatively weak electron-phonon interaction and semimetallic ground state in Lu 2 Ir 2 O 7 , supported by DFT calculations. Low-temperature properties of Lu 2 Ir 2 O 7 were studied by means of magnetization, ac-susceptibility and specific heat measurements. Our low-temperature measurements reveal a bifurcation of ZFC and FC magnetization data below 140 K, which is further pronounced as a broad anomaly in the temperature development of specific heat and ac-susceptibility. The anomaly can be attributed to the same physical mechanism as discussed for other A 2 Ir 2 O 7 with A = magnetic rare-earth element, i.e. to short-range correlations among Ir4+ magnetic moments, rather than to a long-range order of Ir sublattice reported earlier. The ac-susceptibility data revealed a strong frequency dependence of the signal, a paradigmatic sign of a spin-glass transition. The analysis of low-temperature specific heat data brought important information on physical properties of Lu 2 Ir 2 O 7 , in striking agreement with our density functional theoretical (DFT) calculations, concluding relatively weak electron-phonon interaction and semimetallic ground state in Lu 2 Ir 2 O 7. [ABSTRACT FROM AUTHOR]

Pure hydride of the α -UH3 type without any β-UH3 admixture was prepared by high-pressure hydrogenation of bcc U stabilized by Zr. Such material, characterized by a general formula (UH3)1-xZrx, is stable in air at ambient and elevated temperatures. H release is observed in the range of 400-600 °C similar to β-UH3. Its stability allowed us to measure the magnetic properties, specific heat, and electrical resistivity in a wide temperature range. Despite the rather different crystal structure and inter-U spacing, the electronic properties are almost identical to β-UH3. Its ferromagnetic ground state with Curie temperature TC≈180 K (weakly and nonmonotonously dependent on Zr concentration) and U moments of 1.0 µB indicate why mixtures of α- and β-UH3 exhibited only one transition. Magnetic ordering leads to a large spontaneous magnetostriction ωs=3.2 × 10-3, which can be explained by the increase of the spin moment between the paramagnetic (disordered local moment) and the ferromagnetic states. The role of orbital moments in magnetism is indicated by fully relativistic electronic structure calculations. [ABSTRACT FROM AUTHOR]

Abstract: Results of magnetization (M), AC-susceptibility , specific heat (C) and electrical-resistivity measurements on DyFe2Si2 single crystals are reported and analyzed in conjunction with first-principles electronic-structure calculations. Clear anomalies in the , and dependences indicate a magnetic-phase transition (paramagnetic ↔ antiferromagnetic) at 3.8K. Magnetic and specific-heat data obtained in magnetic fields (B) manifest uniaxial magnetocrystalline anisotropy with the easy magnetization direction along the c-axis of the tetragonal structure. These findings together with the metamagnetic transition observed on the curve measured at 2K and the evolution of the specific-heat anomaly at 3.8K in a magnetic field applied along the c-axis corroborate a scenario for the physics of DyFe2Si2 in terms of antiferromagnetism with Néel temperature . The first-principles electronic-structure calculations confirm the absence of an ordered Fe moment, which is in agreement with previously reported experimental findings. The magnetization isotherms and the temperature dependences of the specific heat and paramagnetic susceptibility in the paramagnetic state were analyzed taking into account the crystal-field interaction. The experimentally determined crystal-field parameters are compared with the results of first-principles crystal-field calculations. [Copyright &y& Elsevier]

Structural studies by means of powder X-ray diffraction and single-crystal neutron diffraction show that URhGe crystallizes in the orthorhombic TiNiSi-type of structure. Combined magnetic, electrical-transport and thermal studies performed for the first time on a single crystal confirm ferromagnetic order of URhGe below 9.6 K. In contrast to previous powder neutron-diffraction experiments, our single-crystal results point to collinear ferromagnetic order of U moments of 0.35±0.08 μB confined to the b–c plane, i.e. with no component along the a-axis, which is the hard-magnetization direction in URhGe. Our findings regarding the magnetic properties are in good agreement with theoretical first-principle calculations. [Copyright &y& Elsevier]