High-coercivity Co-ferrite thin films on SiO2(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 SiO₂ 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°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°C or higher. High coercivity was obtained after annealing at 900-1000°C. High coercivity was associated with nanostructure. Hysteresis loops of the samples were annealed at 900°C. It has been found out that substrate also played an important role. Similar trend of magnetic properties was observed in PLD-derived samples.