Al-substitution effects on the magnetic properties of RCo5 (R=Y, Pr, Nd, and Sm)

Abstract

Al substitution effects on the magnetic properties of RCo5 (R=Y, Pr, Nd, and Sm) are studied on the basis of magnetic measurements for RCo5−xAlx with x less than 2. The Al substitution considerably decreases the Curie temperature, the Co-sublattice moment, the magnetocrystalline anisotropy of the R sublattice as well as of the Co sublattice. The Co-sublattice moments in RCo5−xAlx have a different value depending on their directions in the crystal; in addition the rare earth moments are considerably smaller than the values of their free trivalent ions. The decrease of Co-sublattice moment with increasing content of Al can be explained by the rigid band model, and the properties of rare earth sublattices (or atoms) mentioned above seem to be explained by the exchange field at the rare earth site which weakens with increasing Al content.