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Обсуждены результаты исследования структуры и свойств трехкомпонентных сплавов Ni 47−x Mn 42+x In 11 (0 ≤ x ≤ 2) после термоциклической обработки. Показано, что после многократных циклов нагрева и глубокого охлаждения наблюдаются изменение формы границ зерен и повышение микротвердости. Термоциклическая обработка не вызывает существенного изменения магнитной восприимчивости исследованных сплавов.

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The magnetization of a quasisingle-crystalline La 0.75 Sm 0.25 Mn 2 Si 2 sample was measured under high pressures to P = 1.2 GPa. The compound exhibits four different spontaneous magnetic phase transitions: the ordering of Sm sublattice at a critical temperature T Sm = 14 K, the ferro-antiferromagnetic phase transition at T AF = 150 K, the Curie temperature of the ferromagnetic phase at T C = 305 K, and finally, the transition to the paramagnetic state at T P = 403 K. The changes of the critical temperatures of the spontaneous magnetic phase transitions under pressure are −0.6, +203, −12, and ϳ−60 K / GPa, respectively. The temperature range of ferromagnetic phase shrinks with increasing pressure, and at P ജ 0.6 GPa no ferromagnetic ordering of Mn magnetic moments is observed. For the antiferromagnetic phase, application of a relatively low magnetic field produces a sharp first-order field-induced metamagnetic transition. The critical field of the metamagnetic transition depends on the direction of applied field and increases with increasing pressure. The nature of various magnetic phase transitions in RMn 2 X 2 compounds is discussed using a thermodynamic analysis of the obtained results and a phenomenological model of the step change of Mn-Mn interlayer exchange interaction at the transition.

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