ROTATIONAL SPIN-GLASS PROPERTIES OF NEARLY FERROMAGNETIC TB0.15Y0.85ZN

For this cubic pseudobinary compound, the bifurcation of the magnetization (M) vs temperature for warming and cooling in low fields (after zero-field cooling) indicates a spin-glass freezing point (T(g)) of approximately 20 K. Isotherms of M vs cooling field show zero spontaneous moments down to 4.2 K but an initial susceptibility that almost diverges below T(g). From rotational measurements of M as a vector in a fixed field (H) at 4.2 K, the anisotropy field produced by field cooling (H(K)) is found to turn rigidly with the sample for H below approximately 1 kOe. At higher H, H(K) rotates up to some angle relative to H and then stays fixed as the sample continues to turn, thus exhibiting a fractional rotation relative to the sample. Nevertheless, H(K) remains sizeable in magnitude (approximately 12 kOe). Comparisons are made with analogous results for isostructural (Tb, Y) Ag, where spin-glass order coexists with antiferromagnetism, as well as for various prototypal spin-glass alloys.