Determination of Critical Exponents in a Metallic Glass: FeCrCuNbSiB

A. ROSALES-RIVERA; J.C. HERNÁNDEZ-PARRA; J. LÓPEZ-TABARES; A. HINCAPIE-BEDOYA; A.A. VELÁSQUEZ-SALAZAR; D.F. GÓMEZ-MONTOYA; F. D. SACCONE

Barcelona

Conferencia; ICM 2015; 2015

Sociedad Española de Magnetismo

In this work we describe the universality class of FeCrCuNbSiB alloy system by determining the critical exponent  for the spontaneous magnetization. These materials were prepared as amorphous alloy ribbons of Fe73.5-xCrxCu1Nb3Si13.5B9 with x = 0, 2, 4, 6, 8 and 10 (at.%) by means of the melt spinning technique. The temperature dependence of the magnetization of each sample was measured using a vibrating sample magnetometer. We have determined, for each value of x, the critical exponent  for the spontaneous magnetization and the critical temperature TC. The  values found were 0.337  0.010, 0.336  0.008, 0.365  0.005, 0.391  0.005, 0.400  0.004 for x = 0, 2, 4, 6 and 8, respectively. In sample x = 10 was not possible to determine a reliable  value. The  value shows a quasi-linear dependence on the Chromium content and, interestingly goes through values that belong to the Ising (sample with x = 0), X-Y (sample with x = 2) and Heisenberg (sample with x = 4) models, respectively, before finally deviating of any of these models in the high x region (samples with x = 6, 8 and 10). The possible mechanisms leading to such universality classes including the spin-orbit interaction, shape anisotropies, direct exchange and itinerant exchange are analyzed.