FMR and Magnetic Studies on Polycrystalline YIG Thin Films Deposited Using Pulsed Laser

Ferromagnetic resonance (FMR) and magnetic studies have been carried out on polycrystalline YIG films deposited by pulsed laser deposition (at T_S:750 °C, O₂:5×10^-2 mbar) using a range of laser energies (240 to 350 mJ). The films were ex situ annealed (T_a:700 °C, in air for 2 h). The film thickness increases from 100 to 290 nm for an hour of deposition with the increase in laser energy from 240 to 350 mJ. The FMR linewidth was found to reduce from 340 to 70 Oe for the same incremental variation in laser energy. Multiple resonance modes were observed in the perpendicular FMR spectra of our samples which are related to intrinsic as well as extrinsic mechanisms such as in homogeneities. Saturation magnetization measurement (M_s) is found to be dependent on the laser energy. The value of M_s is found to increase with laser energy and is close to 90% of the bulk value for the film with highest power. An attempt has been made to correlate the magnetization results with the microstructure.