Magnetic properties of NdMn12−xNix alloys

Abstract

The RMn12−xTx alloys where R denotes rare earth element and T denotes Fe, Co and Ni have been a subject of intense investigation. Here, we present the magnetic properties of the NdMn12−xNix system, which exists as a single phase for 3.6≤x≤6, and crystallizes in the tetragonal ThMn12 type of structure (space group: I4/mmm). The magnetic susceptibility of these alloys has been examined at the temperature T=1.9–300K, in a magnetic field of 5kOe with a SQUID magnetometer. The field dependence of the magnetization has been obtained at T=1.9K up to 50kOe, and at T=4.2K up to 140kOe. The magnetic susceptibility, χ, follows a modified Curie–Weiss law above about 100K and at low temperatures some anomalies are seen in the χ(T) plot. The linear dependence of magnetization versus magnetic field at low temperature excludes a magnetic ordering of ferromagnetic character. Also, the absence of any maximum in the temperature dependence of the magnetic susceptibility suggests that the anomalies do not have intrinsic character and the investigated alloys are nonmagnetic (paramagnetic).