Effect of chromium addition on the properties of sputtered strontium ferrite films

Hexagonal strontium ferrite (SrM) thin films with various Cr composition in the range of 0-36 at. % were sputtered on the thermally oxidized silicon w afers at the substrate temperature of 550 degrees C using targets of compos ition of SrFe8Ox. It was found that the SrM grows with its c axis oriented perpendicularly to the film plane and its c-axis orientation was improved b y Cr addition in the range of 9-36 at. %. The saturation magnetization and coercivity in the perpendicular direction were about 150 emu/cm(3) and 2.8 kOe, respectively for 9 at. % of Cr addition. The grain size observed at th e surface was 80 nm and the surface roughness was 11 nm. (C) 2000 American Institute of Physics. [S0021-8979(00)94308-1].