Magnetism and spin-reorientation temperatures of Pr2-xYxCO14B and Nd2-xYxCo14B systems

Measurements of the lattice parameters, saturation magnetic moments, Curie temperatures, spin-reorientation temperatures and anisotropy fields have been carried out on the systems Pr2-xYxCo14B and Nd2-xYxCo14B for x = 0.0,0.5,1.0,1.5,1.8 and 2.0. A slight increase in the Curie temperature is observed on replacing Pr or Nd with Y and is attributed to the lattice contraction which results in increased Co-Co interaction. Two spin-reorientation transitions, one at low temperature (TSR1) from conical to axial anisotropy and the other at high temperature (TSR2), from axial to planar anisotropy, are observed in the Nd system, while a single transition at TSR2is observed in the Pr system. The temperature TSR2decreases with decreasing Pr or Nd concentration, indicating its origin in the single ion rare earth anisotropy. TSR1in the Nd system increases with decreasing Nd concentration and can be understood in terms of relative importance of the transition metal anisotropy.