Hall resistivity of a magnetic amorphous alloy — Effects of thermal cycling and annealing

Abstract We have studied the effects of thermal cycling and annealing on the Hall resistivity ϱ H and electrical resistivity ϱ of an amorphous magnetic material, Metglas 2826A. Thermal cycling up to 600 K has no significant effect on ϱ but changes ϱ H , especially at T > 300 K. Annealing at higher temperatures T a affects ϱ H more strongly that it influences ϱ. For T a = 650 K the Curie temperature jumps by ∼300 K and this, combined with X-ray data, is regarded as being symptomatic of the onset of crystallization. It is demonstrated that, for a fixed T , the variation of the extraordinary Hall coefficient R 1 is simply correlated with that of ϱ for both the amorphous material and the annealed (crystallized) specimens. Furthermore, for a given T a , the variations of R 1 and ϱ as functions of temperature exhibit the same formal relationship. The temperature dependence of ϱ in the annealed specimens is rendered plausible in terms of recent theories of disordered materials. Room-temperature studies of electron spin resonance and the field dependence of the magnetization are also reported.