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The field dependence of magnetization at T = 4.2 K and in magnetic fields of up to 70 kOe, temperature dependences of magnetization (2 K < T < 300 K), heat capacity (2 K < T < 30 K) and magnetic susceptibility (2 K < T < 1000 K) for Mn1.99Co0.96Al1.05 and Mn1.79Co1.25Al0.96 alloys, closed in composition to the Mn2CoAl spin gapless semiconductor, were studied. Alloys studied were demonstrated to be the band ferromagnets. Their high-field (H > 11 kOe) magnetization is described in the Stoner models with the Rhodes-Wohlfarth parameter pRW = 1.3 for Mn1.99Co0.96Al1.05 and pRW = 2.3 for Mn1.79Co1.25Al0.96. When the composition deviates from the stoichiometric Mn2CoAl, the spontaneous moment decreases slightly, the effective moment, on the contrary, increases. In this case, a negative sign of the temperature-independent component of the paramagnetic susceptibility is observed. The density of states n(EF) at Fermi level and the Debye temperature ΘD of studied alloys have the usual values for 3d-metal alloys. [ABSTRACT FROM AUTHOR]

The dynamics of low-density trapped magnetic fluxes, including local fluxes, are investigated in single-crystal YBCO in the region of strong thermal fluctuations near the superconducting phase transition. A substantial difference of the isothermal magnetization-relaxation behavior from the quasi-logarithmic behavior observed earlier in strong magnetic fields is established for the first time. The effective pinning potential in the temperature interval close to the critical temperature is estimated in terms of the simplest model of thermally activated creep. [ABSTRACT FROM AUTHOR]

The exchange coupling of magnetically ordered layers (MOLs) through a nonmagnetic metallic spacer is calculated. The induced magnetization in the spacer, taking into account the influence of an external magnetic field, is calculated, too. This calculation shows that the energy of coupling of the MOLs through the nonmagnetic metallic spacer is a long-periodic function of the spacer thickness and magnetic field, i.e., the exchange coupling between the layers varies from ferromagnetic to antiferromagnetic and vice versa depending on the spacer thickness and magnetic field. Also this calculation shows that in nonferromagnetic spacer the induced magnetization can undergo many complete rotations, depending on distance to the boundaries with the MOLs. Moreover, absolute value of the induced magnetization decays nonmonotonically with distance from the interfaces inside the spacer. It is shown that the character of the decay of the absolute value of the magnetization from the interfaces into the interior of the spacer is influenced by magnetic field. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

This paper discusses the temperature and field dependences of the magnetization of the nanocomposite compound GdNiO3 in the temperature interval 0.5–150 K in magnetic fields up to 14 T. The temperature dependences of the heat capacity are also investigated in magnetic fields up to 9 T. Anomalies of the static susceptibility, heat capacity, and dynamic magnetization are detected at temperatures of 0.7, 1.6, and 13 K, respectively. The detected anomalies are associated with magnetic phase transitions. [ABSTRACT FROM AUTHOR]

This paper discusses the temperature and field dependences of the magnetization of the nanocomposite compound GdNiO3 in the temperature interval 0.5–150 K in magnetic fields up to 14 T. The temperature dependences of the heat capacity are also investigated in magnetic fields up to 9 T. Anomalies of the static susceptibility, heat capacity, and dynamic magnetization are detected at temperatures of 0.7, 1.6, and 13 K, respectively. The detected anomalies are associated with magnetic phase transitions. [ABSTRACT FROM AUTHOR]