Deposition of CoPtP films from citric electrolyte

Magnetically hard CoPtP (up to 40 μm thickness) films for MEMS application were deposited from citrate electrolyte and considered in terms of their composition, structure, magnetic characteristics and deposition conditions. Films containing 83-92 at.% (a/o) Co were deposited in the presence of NaH₂PO₂ in the electrolyte, with current efficiency of about 20% (deposition rate 10-12 μm/h). Coercivity 2.7-2.8 kOe and remanence 3.0 kG were achieved magnetizing in the direction normal to the film plane. According to XRD analysis, films seem to consist of hexagonal phase of CoPt solid solutions. Current efficiency, composition and morphology of the films, as well as their magnetic characteristics, were influenced by the electrolyte prehistory and total charge passed through the electrolyte in previous operation.