Effects of substrate temperature on the magnetic and electrical propertiesof cobalt ferrite metal composite thin films

The magnetic and electrical properties of the cobalt ferrite/metal composit e thin films, prepared by reactive sputtering, were studied as a function o f substrate temperature. With increasing substrate temperature, the saturat ion magnetization of the thin films increased owing to precipitation of the Co0.67Fe0.33 phase. Also, the electrical resistivity of the thin films dec reased. From Hall experiments, the decrease of electrical resistivity of th e composite thin films was mainly attributed to the increase of electron co ncentration. The Seebeck coefficient measurement shows that the electrical conduction mechanism of the thin films containing 37.8 and 33.7 at % Co cha nges from p-type to n-type and that of the thin films containing 28.5 at % Co remains n-type with increasing substrate temperature. This might be attr ibuted to the change in composition of the cobalt ferrite matrix to Fe-exce ss with precipitation of Go-rich Fe alloy. (C) 1999 Kluwer Academic Publish ers.