Study of magnetic and magneto-optical properties of heavily doped bismuth substitute yttrium iron garnet (Bi:YIG) film

Abstract

The magnetic and magneto-optical properties of heavily doped Bi: YIG film were studied. The film was deposited by radio frequency magnetron sputtering method and crystallized by rapid recurrent thermal annealing (RRTA). The results show that the RRTA treated film has good properties both in microwave and optical wave band. The saturation magnetization of the film on different substrates varies from 135. 7 to 138.6 kA·m−1. The coercive field of the film on GGG substrate is about 0.32 kA·m−1 while about 0.8–1.43 kA·m−1 on YAG substrate and 1.75 kA·m−1 on Al2O3 substrate. The Faraday angle is about 3 – 5 (°)·μm−1 when optical wavelength ranges at 450 – 600 nm. The transmission spectra of the Bi: YIG films on three substrates has similar change as annealing temperature below 800 °C. Specially, when annealing temperature is above 800 °C a step is observed between 550 and 650 nm wavelength for the film deposited on Al2O3 substrate. Three results are very useful in magneto-optical recording application and integrated microwave devices.