THE ROLE OF BORON IN RN+1CO3N+5B2N SYSTEMS (R = Y, SM, DY, N = 0, 1, 2, 3, AND INFINITY)

Magnetic measurements have been made for the systems of Rn+1Co3n+5B2n (R=Y, Sm, Dy; n=1, 2, 3, 4, and infinity in wide temperature region. The Curie temperature decreases drastically between n=0 and n=1, and slowly with n larger than 1, for all above systems. Three kinds of Co sites with different magnetic moments are proposed. The estimated Sm- and Dy-atomic moments are found to be smaller than the free ion moments in the Dy system with n > 1 and in the Sm system. Magnetic anisotropy constants K1 (Co) and K2 (Co) have been determined at various temperatures for the Y system, and the Sm-sublattice anisotropy constants K1 (Sm) have been estimated and found to take the maximum value at n=1 and decrease with n > 1 in the Sm system. Magnetic anisotropy in the Dy system is found to be planar at all temperatures below the Curie temperature.