Magnetic properties of CdSb doped with Ni

Magnetic properties of the group II-V semiconductor CdSb single crystals doped with Ni (2 at%) are investigated. Deviation of the zero-field-cooled susceptibility, χZFC, from the field-cooled susceptibility is observed below 300 K, along with a broad maximum of χZFC (T) at Tb in fields below the anisotropy field BK∼4 kG. Tb(B) obeys the law [Tb(B)/Tb(0)]1/2=1-B/BK with Tb(0)∼100 K. The magnetization exhibits saturation above ∼20-30 kG, a weak temperature dependence and anisotropy of the saturation value Ms. The coercive field is much smaller then BK and displays anisotropy inverted with respect to that of Ms. Such magnetic behavior is expected for spheroidal Ni-rich Ni1−xSbx nanoparticles with high aspect ratio, broad distribution of the sizes and with orientations of the major axis distributed around a preferred direction.