The mechanism of Ag top layer on the coercivity enhancement of FePt thin films

The magnetic properties of the FePt thin films with a Ag top layer prepared by magnetron sputtering have been studied. With 4 nm Ag layer deposited right after the deposition of FePt layer, the ordering temperature of the L1(0) FePt phase decreased to 350 degrees C or below. X-ray photoelectron spectroscopy results indicate that Ag has diffused into the FePt layer when Ag was deposited at 350 degrees C, while Ag remains on the top of the FePt when Ag was deposited at room temperature. The Ag top layer deposited at 350 degrees C was also found to protect the FePt layer from oxidation. (c) 2005 American Institute of Physics.