Magnetic Phase Transition of Epitaxial γ-Fe/Cu and α-Fe/Au Artificial Superlattices

Abstract

The magnetic critical exponent β and Curie temperature (T_c) of epitaxial γ-Fe/Cu and α-Fe/Au artificial superlattices prepared by the molecular beam epitaxy (MBE) method have been investigated. The critical exponent β in the relationship M/M_s = (1-T/T_c)^β is estimated to be 0.30±0.02 and 0.18±0.02-0.57±0.02, respectively. The Curie temperature is decreased with decreasing Fe layer thickness. The behavior is explained by taking into account of the number of nearest - neighbor Fe atoms around an Fe atom.