Magnetocrystalline anisotropy and spin reorientation in Gd1-xDyxCo4B

Magnetic measurements at various temperatures have been performed for loose powder and held-oriented samples of Gd1-xDyxCo4B with x=0, 0.05, and 0.1. The temperature dependences of spontaneous magnetization in these compounds are determined. It is found that a spin reorientation occurs at around T=162 K for Gd0.95Dy0.05Co4B and at around 225 K for Gd0.9Dy0.1Co4B. The temperature dependences of magnetic anisotropy constants, K-1(Gd1-xDyxCo4B), of Gd1-xDyxCo4B with x=0 and 0.1 are determined. The anomalous temperature dependence of K-1(GdCo4B) is well explained by taking account of the Gd sublattice magnetic anisotropy due to the dipole-dipole interaction and the Co sublattice magnetic anisotropy similar to that in YCo4B. The temperature dependence of the Dy sublattice magnetic anisotropy constant, K-1(Dy), has also been determined by making use of K-1(GdCo4B) and K-1(Gd0.9DY0.1Co4B). (C) 1996 American Institute of Physics.