Magnetization and specific heat studies of RNi4Ga (RSm, Gd and Tb)

In order to elucidate the anomalous magnetic properties in the ferromagnetically ordered state of SmNi4Ga GdNi4Ga and TbNi4Ga, we have carried out a detailed study with magnetization and specific heat (SH) measurements. GdNi4Ga shows the possibility of a filled 3d band and a helical spin arrangement below the ordering temperature. TbNi4Ga shows a dominant crystal field effect resulting in a deviation of TC from the de-Gennes scaling and possible Schottky anomalies in the SH. SmNi4Ga shows a large coercivity at low temperatures. A rough estimate of the domain wall thickness in SmNi4Ga gives a value of 8 Å.