Magnetic properties of vapor-deposited iron–noble-metal multilayers

A vapor-deposition technique was employed to investigate the magnetic properties of iron--noble-metal multilayers. The thickness, periodicity, chemical composition, microstructure, and the magnetic moment of the films were characterized and measured by various methods. The experimental results indicated that the magnetic moment per Fe atom in iron--noble-metal multilayers was significantly enhanced with decreasing Fe-layer thickness, with a fixed noble-metal thickness. The magnetic enhancement was found to be up to 120% for Fe(4.5 nm)/Au(7.5 nm), 120% for Fe(1.2 nm)/Ag(9 nm), and 160% for Fe(1.5 nm)/Cu(7.5 nm) multilayers, respectively, within an error of 6%. Also, when the thickness of the Fe layer decreased, there was an increasing tendency for perpendicular magnetization in the iron--noble-metal multilayers. The possible mechanism of the magnetic-moment enhancement is discussed in terms of the metastable atomic configuration of Fe atoms at the iron--noble-metal interfaces.