Amorphous yttrium-iron alloys. I. Magnetic properties

Abstract

The magnetic properties of amorphous yttrium-iron alloys Y_1-xFe_x have been studied over a wide concentration range 0.32H, but the susceptibility maximum occurs at a lower temperature, T_M. These properties are characteristic of a spin glass. Competing exchange interactions of both signs, which stabilise helimagnetic structures in some crystalline R₂F₁₇ alloys, lead in the amorphous state to spin-glass behaviour and asperomagnetic order. The dominant positive interactions produce short-range ferromagnetic correlations which persist up to room temperature. However magnetic saturation cannot be achieved for any of the alloys in applied fields of up to 180 kOe, indicating that strong negative interactions are also present.