High-coercivity Co-ferrite thin films on SiO/sub 2/(100) substrate prepared by sputtering and PLD

Co-ferrite thin films are interesting for magnetic recording and magneto-optical devices. In this work, we have prepared Co-ferrite thin films on SiO/sub 2/ substrate with high coercivity by sputtering and PLD. The film thickness was around 50 nm. All the films were subsequently annealed at a temperature of 500 to 1000/spl deg/C. As-sputtered Co-ferrite film possessed an amorphous-like structure, as no X-ray diffraction peak was observed. Crystallization required an annealing at 500/spl deg/C or higher. High coercivity was obtained after annealing at 900-1000/spl deg/C. High coercivity was associated with nanostructure. Hysteresis loops of the samples were annealed at 900/spl deg/C. It has been found out that substrate also played an important role. Similar trend of magnetic properties was observed in PLD-derived samples.