SUBSTRATE-TEMPERATURE AND OXYGEN-PRESSURE DEPENDENCE OF PULSED LASER-DEPOSITED SR FERRITE FILMS

The effect of substrate temperature and oxygen pressure on the microst ructure, magnetic and magneto-optical properties of Sr ferrite (SrM) f ilms grown on (001) single-crystal sapphire substrates by pulsed laser deposition has been investigated. Polycrystalline SrM films with perp endicular magnetic anisotropy could be prepared under a wide range of oxygen pressures and relatively high temperatures, sufficient to cryst allise the material. However, an almost exclusive c-axis orientation n ormal to the film plane could be attained only at a narrow operational window centred at 0.1 mbar and 840 degrees C. The magneto-optical pro perties of the films were comparable to those of the bulk barium hexaf errite single-crystal material. In addition, results obtained by atomi c force microscopy provide convincing evidence that the growth of Sr f errite on sapphire takes place by a spiral growth mechanism.