Markayendeyulu G

X-ray powder photographs on Ho0.85Tb0.15Fe 2Hx (x=0-3.1) and Dy0.73Tb 0.27Fe2Hx (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 Dy 0.73Tb0.27Fe2 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 Dy 0.73Tb0.27Fe2 system. The temperature variation of magnetization of Ho0.85Tb0.15Fe2H x and Dy0.73Tb0.27Fe2Hx suggests the occurrence of a spin-reorientation transition.

Magnetization measurements have been performed along and perpendicular to the c-axis of Mn1.1Sb single crystal in the temperature range 293K-512K using a vibrating sample magnetometer. Spin reorientation transition has been found to occur at 380K. The temperature variation of saturation magnetization exhibited an anomaly around 380K which is attributed to the occurrence of the spin reorientation transition. The first order magnetocrystalline anisotropy constant (K1) has been evaluated employing the equation for the magnetization curve along the hard direction of magnetization. At 293K, K1is evaluated to be -6.8xl04J/m3and above 380K it is found to become positive indicating the occurrence of spin reorientation at 380K. © 1987 IEEE

Magnetocrystalline anisotropy in single crystals of MnSb was studied as a function of temperature using FMR. The first-order anisotropy constant K1 was calculated to be -12.99x104 J m3 at 300 K. K1 was observed to become positive above 520 K indicating the occurrence of a spin reorientation transition. An attempt is made to understand the origin of spin reorientation phenomenon. © 1987.