High-temperature evolution of coercivity in nanocrystalline alloys.

Abstract

The temperature evolution of the coercivity of a Finemet-type alloy, in which 10 at. % Fe has been substi- tuted by Cr and annealed at different temperatures, has been studied. In the temperature region above the coercivity maximum, the experimental hysteresis loops have been successfully fitted by a combination of two models which use effective field controlled memory effects and temperature rescaling to describe dipolarly interacting superparamagnetic particles. It is shown that the characteristic parameters of these two models ~ interaction temperature and interaction field ! are interrelated. A consistent two-step fitting procedure was developed which yielded physically meaningful values for the temperature dependence of the magnetic mo- ment of the particles.