Magnetic properties of thulium-hydrogen solid solutions

Abstract

Low-temperature magnetisation measurements for various fields (10-50 kOe) on solid solutions of alpha TmH_x (x taking values from 0 to 0.1) have revealed a decrease of T_N and T_C with increasing x; the deduced values of the paramagnetic Curie temperature, theta _p, and of the effective paramagnetic moment, mu _eff^p, also decrease with increasing x. The saturation magnetic moment, mu _sat(0), increases with increasing field, the addition of hydrogen accelerating this increase. The results are explained in the framework of the RKKY model, assuming an H-H pair structure for the hydrogen configuration, which favours the magnetisation due to the c axis alignment of both pair axis and spins.