Transition to superparamagnetism in a Cr-containing Finemet alloy

Summary form only given. Soft magnetic nanocrystalline alloy microstructure consists of ferromagnetic crystals with grain sizes in the nanometer range, embedded in a ferromagnetic amorphous matrix. In order to extend the temperature range in which the transition to superparamagnetic behavior can be studied, Fe has been partially substituted by Cr in a Finemet-type alloy. This has the effect of separating the two limiting temperatures for detecting superparamagnetic behavior, the lower being the Curie temperature of the remaining amorphous matrix, and the upper the temperature at which further structural evolution of the nanocrystalline alloy takes place. Hysteresis loops have been measured from 100 K to 700 K.