Structure and Magnetic Properties of the γ'-Fe₄N Films on Cu Underlayers

The γ'-Fe₄N films on Cu underlayers are deposited on the glass and Si substrates by dc magnetron reactive sputtering. The effects of Cu underlayer on the structure, morphology and magnetic properties of the γ'-Fe₄N films are studied. The single-phase γ'-Fe₄N films with Cu underlayers on the glass substrate are obtained, while the mixture of Fe and γ'-Fe₄N is observed on the Si substrate. In comparison with the films without Cu underlayers, the grains of the films with Cu underlayers exhibit a non-uniform size distribution and give rise to a rougher surface. The magnetic measurements indicate that the γ'-Fe₄N films show a good soft ferromagnetic behavior. The enhanced coercivity in the films with Cu underlayers is observed due to the deterioration of the crystallographic structure as well as the rougher surface.