Spin-glass-like static and dynamic properties of mechanically alloyed Fe–Re–Cr.

We report the observation of spin-glass-like features in a Fe[sub 61]Re[sub 30]Cr[sub 9] sample obtained after high energy milling for 460 h. X-ray diffraction showed a broad nanocrystalline peak. The zero-field-cooled and field-cooled magnetization curves exhibited a clear irreversibility, the former showing a relatively sharp maximum for low fields at T[sub max]approx. 60 K. In addition, the temperature dependence of the magnetic AC susceptibility (χ[sub ac]) also showed a peak at approximately the same temperature. The frequency sensitivity of such maximum (p=ΔT[sub max]/T[sub max]Δ log wapprox. 0.02) is small compared to that of typical superparamagnets. However, we discuss the insufficiency of this set of phenomena to assert the existence of a true spin-glass transition and propose the blocking of interacting ferromagnetic nanoparticles as the origin of the observed behavior. The effect of annealing, rendered into nanocrystallite growth, on the χ[sub ac] maximum is studied in an attempt to test this explanation. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]