Magnetic and electrical studies on Ho<inf>0.85</inf>Tb <inf>0.15</inf>Fe<inf>2-x</inf>Ni<inf>x</inf> system

Cubic Laves phase alloys of Ho0.85Tb0.15Fe 2-xNix (0≤x≤2) were prepared and the lattice parameters, evaluated as a function of x at room temperature, show deviation from Vegard's law. This was attributed to the presence of a magnetovolume effect and charge transfer. Magnetization measurements were performed in the temperature range 77-700 K. The results suggest that the system undergoes a gradual transition from ferri- to ferromagnetic with increasing x. This has been explained based on the 3d band model. Furthermore, a monotonic decrease in Curie temperature with x was observed. Electrical resistivity studies were carried out in the temperature range 16-700 K. An anomaly was found in the vicinity of the Curie temperature for x=2 which has been attributed to the existence of the long-range nature of the critical fluctuations due to short-range spin ordering.