Linear and Nonlinear Susceptibilities of Amorphous Fe-RE-Zr (RE=Ho,Dy,Er) Alloys

Linear and nonlinear AC susceptibilities are examined for mechanically alloyed amorphous (Fe1-xREx)0.7Zr0.3 (x≤0.4; RE=Ho, Dy and Er) which exhibit spin freezing behaviors due to the random magnetic anisotropy of RE atoms. A negative divergent behavior of nonlinear susceptibility χ2 is observed for the specimens with x=0.1, similar to a case of a spin-glass ordering. On the other hand, for the specimens with x=0.3, χ2 is found to show an antisymmetric anomaly, indicating a ferromagnetic ordering. Such behaviors reveal a reentrant-spin-glass-like ordering character of the specimens with x=0.3 at zero DC field. The magnetic phase diagrams are proposed and the ordering characteristics of the systems are discussed with a systematic change of the RE concentration.