RANDOM ANISOTROPY AND EXCHANGE IN AMORPHOUS R7-XR'NI3

Magnetic order in amorphous alloys of Y7-xGdxNi3, Gd7-xDyxNi3 and Dy7-xYxNi3 (0 less-than-or-equal-to x less-than-or-equal-to 7) has been characterised using ac susceptibility and dc magnetisation techniques. While Y7-xGdxNi3 alloys exhibit a simple percolative transition from a spin glass state to ferromagnetism, alloys containing Dy show clear evidence of random magnetic anisotropy leading to correlated speromagnetic and speromagnetic phases.