High-coercivity Co-ferrite thin films on SiO2 (100) substrate prepared by sputtering and PLD

Abstract

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 shown in Fig. 1, 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, as shown in Fig. 2. High coercivity was associated with a nanostructure, as shown in Fig. 3. Hysteresis loops of the sample annealed at 900°C were shown in Fig. 4. It has been found out that substrate also played an important role, as shown in Table 1. Similar trend of magnetic properties was observed in PLD-derived samples. © 2005 lEEE.