Fabrication of Bi-doped YIG optical thin film for electric current sensor by pulsed laser deposition

Bi-doped yttrium iron garnet (BixY3−xFe5O12, Bi:YIG) thin films, which can be used as electric current sensors, are grown on Gd3Ga5O12 (GGG) substrates by pulsed laser deposition (PLD) using an ArF excimer laser. The growth condition for high quality epitaxial Bi:YIG thin films is investigated by varying the PLD process parameters, such as the substrate temperature and ambient oxygen gas pressure. The epitaxial film growth is attained at the substrate temperature of around 500 °C and at ambient oxygen pressure between 125 and 175 mTorr. The optical properties of epitaxial films are measured and the maximum magneto-optic sensitivity coefficient is observed to be 44.1°/T with a film thickness of about 0.7 μm at a wavelength of 500 nm. The results indicate that the PLD technique can be useful for realizing a miniature current sensing device with the Bi:YIG thin film.