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Abstract: We have investigated the crystallographic, magnetic and thermodynamic properties of the as-cast and annealed Ce2NiSi3 alloys, crystallizing in the AlB2-type hexagonal structure. The DC-magnetic susceptibility data show that the as-cast sample exhibits an antiferromagnetic (AFM) ordering below T N = 3.8K, whereas the annealed sample shows, at 4.2K, a magnetic transition of AFM nature and, around 2.5K, an additional anomaly. The specific heat shows a peak with at 3.8K for the as cast sample, which shifts to lower temperatures when the magnetic field increases, consistent with the antiferromagnetic nature of the transition. On the other hand, in the annealed alloy, the maximum of the specific heat peak reaches at 4.2K, and no additional anomalies were observed. The different magnetic behavior between the as-cast and annealed samples is attributed to thermal effects on the structural disorder of nickel and silicon atoms, as already observed in other isotypic R2TSi3 alloys, where R=U or Ce, and T= transition metal. [Copyright &y& Elsevier]

Abstract: We report measurements on the thermal and magnetic properties in the temperature range 2–300K for the compound which crystallizes in the orthorhombic -type structure (space group Cmcm). At zero magnetic field, AC-magnetic susceptibility data show a peak in the real component consistent with an antiferromagnetic order below . A field-induced ferromagnetic order is observed from the zero field cooled and field cooled curves of DC-magnetic susceptibility at different magnetic fields with a transition to a ferromagnetic state between 9 and 10kOe. It is further confirmed by the isothermal magnetization curves as a function of the magnetic field at several temperatures, showing two metamagnetic transitions at and . The results are compared to those reported for other Yb–Ni–Al compounds. [Copyright &y& Elsevier]

Abstract: Hydrogenation of CeNiSn provokes a change of the ground state of cerium from Kondo insulator to antiferromagnetic or ferromagnetic behaviour. We report heat capacity measurements in performed in magnetic fields up to 90kOe. The calculated magnetocaloric effect has a maximum at temperatures close to . The values of the isothermal magnetic entropy and the adiabatic temperature change are modest, and similar to those found in other Ce compounds. The field dependence of both, heat capacity and magnetocaloric effect clearly indicate the nature of the magnetic transition. [Copyright &y& Elsevier]

Magnetization studies have been performed on a polycrystalline sample of Dy5Si3Ge as a function of an applied magnetic field (up to 50 kOe) and hydrostatic pressure (up to 10 kbar) in the 5-300 K temperature range. The anomalous behavior of the magnetic susceptibility indicates that a Griffiths-like phase exists at low magnetic fields and pressures up to 10 kbar. We present evidence that the high-temperature second-order ferromagnetic transition can be coupled with the low-temperature first-order crystallographic transformation into a single first-order magnetic-crystallographic transformation using a magnetic field and hydrostatic pressure as tuning parameters. The effect of pressure on the Griffiths-like phase is reported and analyzed in the framework of the complex competition between the interslab and intraslab magnetic interactions. [ABSTRACT FROM AUTHOR]

Abstract: The functional dependence of the critical current density on magnetic field, , observed at fixed temperatures in the unconventional type-II superconductor, () alloys, but not the relative magnitude of in different alloy compositions at any given temperature and field, is adequately described by the exponential-decay critical state model. In accordance with the predictions of the Kramer''s flux-pinning model, the peak value of the pinning force density with the exponent and scales with , where is the upper critical field. Irrespective of sample composition and temperature in the superconducting state, the pinning of the flux line lattice (FLL) dominates over the plastic FLL shear. [Copyright &y& Elsevier]

Abstract: We report specific heat measurements, in magnetic fields up to 9T, on the Ce2CuIn3 alloy, which exhibits spin-glass (SG) features below . At zero magnetic field, an anomaly associated to the SG transition appears around . This anomaly broadens and shifts to higher temperatures when increasing the magnetic field. The magnetic entropy has the value of at , and increases close to about at . The maximum value for the magnetocaloric effect is obtained at 4.4K, where the isothermal magnetic entropy reaches a value of at the maximum experimentally available field of 9T. We compare our results to those reported for other SG systems. [Copyright &y& Elsevier]

Abstract: The Co2−x Cu x (OH)AsO4 (x=0 and 0.3) compounds have been synthesized under mild hydrothermal conditions and characterized by X-ray single-crystal diffraction and spectroscopic data. The hydroxi-arsenate phases crystallize in the Pnnm orthorhombic space group with Z=4 and the unit-cell parameters are a=8.277(2)Å, b=8.559(2)Å, c=6.039(1)Å and a=8.316(1)Å, b=8.523(2)Å, c=6.047(1)Å for x=0 and 0.3, respectively. The crystal structure consists of a three-dimensional framework in which M(1)O5-trigonal bipyramid dimers and M(2)O6-octahedral chains (M=Co and Cu) are present. Co2(OH)AsO4 shows an anomalous three-dimensional antiferromagnetic ordering influenced by the magnetic field below 21K within the presence of a ferromagnetic component below the ordering temperature. When Co2+ is partially substituted by Cu2+ions, Co1.7Cu0.3(OH)AsO4, the ferromagnetic component observed in Co2(OH)AsO4 disappears and the antiferromagnetic order is maintained in the entire temperature range. Heat capacity measurements show an unusual magnetic field dependence of the antiferromagnetic transitions. This λ-type anomaly associated to the three-dimensional antiferromagnetic ordering grows with the magnetic field and becomes better defined as observed in the non-substituted phase. These results are attributed to the presence of the unpaired electron in the dx 2−y 2 orbital and the absence of overlap between neighbour ions. [Copyright &y& Elsevier]

Abstract: We report changes on the structural and magnetic properties of a crystalline alloy when submitted to high-energy ball milling. The samples were characterized by means of X-ray diffraction, DC and AC susceptibility. The starting compound was found to crystallize in the orthorhombic structure and orders antiferromagnetically at . After 120h of milling time, the atomic structure is basically amorphous and the antiferromagnetic phase disappears giving rise to a spin–glass (SG)-like magnetic arrangement below . [Copyright &y& Elsevier]