Mössbauer measurements of static critical behavior in disorderedFeAlalloys

Abstract

Mossbauer measurementswere made on disordered Fel Al"alloys over the range 0&x &0.04 in order to determine the critical exponent P. It was found, in agreement with theoretical predictions, that P remains unchanged with the addition of disorder. With the use of analysis that contains correction to scaling terms, a mean value of P =0.366(2) was found for five measurements. This is in excellent agreement with the renormalizationgroup prediction of P =0.365{1). A model was developed to help interpret critical behavior . in the presence of a small distribution of critical temperatures observed in the alloy measurements.

Universal correction to scaling amplitude ratios for inhomogeneous ferromagnets with continuous symmetry

“…Extensive studies of the influence of impurities on the critical behavior of the magnetization have been carried out by Hohenemser and co-workers using Mössbauer techniques. For example, from an analysis of their data on polycrystalline Fe 1Ϫx Al x over the range 0рxр0.04, Collins et al 33 determined ␤ϭ0.366(2) to be the mean value of five measurements. The influence of the first-order corrections to scaling was considered.…”

Perturbed angular correlation study of the magnetic phase transitions in the rare-earth cobalt Laves phasesRCo2

“…Critical line broadening near T C has previously been observed in Mößbauer studies of concentrated disordered alloys 31,32 and in PAC measurements of dilute alloys 33 and has been interpreted in terms of a distribution of the exchange coupling, caused by the topological and the chemical disorder present in disordered alloys. 34 The mechanism producing an asymmetric T C distribution in a chemically ordered intermetallic compound is presently not clear.…”