ملخص: We have carried out AC susceptibility, hysteresis cycle and torque measurements on (Ni76-xPdx)Mn24, with 0 [les] x [les] 5, bulk alloys in the temperature and field ranges of 4.2-260 K and 0-20 kG, respectively. The AC susceptibility curves, [chi]′(T), present a maximum at the same freezing temperature, Tg, as the isoelectronic alloy Ni76Mn24. These alloys exhibit also the same Curie temperature, Tc, and the same saturated magnetization, Ms. However, both the unidirectional anisotropy field, Ha, and the coercivity field, Hc, increase considerably with the palladium content. For instance, Ha is 1.5 times larger for (Ni74Pd2)Mn24 than for Ni76Mn24. The torque measurements give approximately the same Ha at 4.2 K as the hysteresis cycle. We conclude that Pd impurities enhance unidirectional anisotropy but have practically no effect on Tc, Tg and Ms. This is ascribed to the greater spin-orbit coupling of palladium.

لغة: إنجليزية