Film Stress and Magnetic Properties of Nickel, Cobalt, Iron and Iron-Cobalt Alloy Electrodeposits

摘要

The electrodeposition of nickel, cobalt, iron and iron-cobalt alloys thin films from additive-free acidic chloride baths with calcium chloride as a supporting electrolyte was investigated. In general, low film stress was achieved by operating at a low current density and higher temperature. SEM micrographs indicated that these conditions promoted grain growth over nucleation. Magnetic properties, including coercivity and squareness, were strongly influenced by film stress. Coercivity in electrodeposited nickel and iron films increased with increasing film stress while squareness decreased, indicating that magnetoelastic energy was the dominant anisotropy in electrodeposited nickel and iron films. No such trends were observed in electrodeposited cobalt films, which indicated that other anisotropy energies (e.g., crystal anisotropy) were dominant. In the case of iron-cobalt thin films, film composition played an important role in determining film stress.