Magnetic instabilities in Er1-xYxCo3 studied by NMR

The field dependence of 59 Co NMR in ferrimagnetic Er 1-x Y x Co 3 was measured up to 8T at 4.2K. For pure ErCo 3 in fields perpendicular to the c axis the resonance frequencies change discontinuously between 2 and 3 T due to a field induced metamagnetic transition. The transition is characterized by rotations of Er and Co magnetic moments away from the easy c-axis. The angles between the Co moments and the c axis at x = 0.1 are obtained. The easy axis is found to be along the c axis for x = 0 and 0.1, and inclined from the c axis for x = 0.3 and 0.5.