High B value Mn-Co-Ni spinel films on alumina substrate by RF sputtering

A series of Mn–Co–Ni–O spinel oxide films showing negative temperature coefficient were successfully deposited on alumina ceramic substrates by RF sputtering procedure. All films showed a poly-crystalline spinel structure. For an Ar:O2 ratio of 10:0, the deposited film showed the highest grow rate and a two-layer-structured Mn–Co–Ni–O spinel film was formed. The high performance of the MCN thin film is testified by a room temperature resistance of 4.16 MΩ, a B value of 5999 K and activation energy of 0.52 eV. These improvements are meaningful, especially concerning industrial applications.