Atom probe compositional analysis of Co-Cr sputtered magnetic thin films

A Co-22 at. % magnetic thin film, sputter deposited on a heated Cu coated Si substrate, was analyzed in the planar direction of the film by atom probe field ion microscopy (APFIM). The atom probe concentration depth profile convincingly showed that the film contained two phases, one enriched in Cr up to 30–35 at. % and the other enriched in Co up to 95–93 at. %. This result indicates that Co-22 at. % Cr thin film deposited on a heated substrate consists of ferromagnetic and paramagnetic phases, each less than a few tens of nanometers in size.