Magnetic and corrosion properties of UHV-deposited Fe_1-xPd _x thin films

Abstract

The magnetic and atmospheric corrosion characteristics of Fe 1-xPdx films are discussed. The polycrystalline films are prepared by codeposition in a UHV system using separate electron-beam-heated Fe and Pd sources. Some trends in their properties appear to be connected with the crystal structure which is bcc for x≲0.31 and fcc for higher Pd concentrations. All but films with high Pd content are magnetically soft or nearly so and have an in-plane uniaxial anisotropy. The anisotropy field decreases with increasing deposition temperature and is also smaller for the fcc structure. The coercivity depends principally on film composition and deposition temperature. Perpendicular anisotropy is found in films with high Pd concentrations. The lower Pd content bcc structure is relatively prone to corrosion in a high-humidity atmosphere containing controlled trace quantities of acid-forming pollutants (Cl2, SO2, etc.), but the fcc structures are quite inert. Possible mechanisms governing the relationship of the magnetic, corrosion, and structural properties to the deposition parameters are explored.