Effect of hydrogen on the magnetic properties of Ho0.85Tb0.15Fe2 and Dy0.73Tb0.27Fe2

X-ray powder photographs on Ho0.85Tb0.15Fe2Hx (x=0–3.1) and Dy0.73Tb0.27Fe2Hx (x=0–3.3) revealed that there is an expansion of the lattice upon hydrogenation. Magnetization measurements were performed using a PAR vibrating sample magnetometer in the temperature range 100–700 K. The total magnetic moment is found to decrease with increase of hydrogen content. The Curie temperature of the hydrides is considerably lowered, though the exact TC in hydrides could not be determined due to desorption. Both Ho0.85Tb0.15Fe2 and Dy0.73Tb0.27Fe2 do not exhibit any compensation, whereas Tcomp is observed and found to decreasse with x in the case of the Ho0.85Tb0.15Fe2Hx system, x=0.18–3.1. No compensation was observed even in the hydrides of the Dy0.73Tb0.27Fe2 system. The temperature variation of magnetization of Ho0.85Tb0.15Fe2Hx and Dy0.73Tb0.27Fe2Hx suggests the occurrence of a spin-reorientation transition.