Target grain size dependence of the morphology, crystallinity and magnetic properties of yttrium iron garnet films

In this work, yttrium iron garnet films were prepared on a Ga3Gd5O12 substrate by pulsed laser deposition. The dependence of target grain size on the morphology, crystallinity, and magnetism of films was investigated. Firstly, X-ray diffraction revealed that the fine grain size of the target was beneficial for increasing the crystallinity of films. Secondly, scanning electron microscopy and roughness measurements displayed the film prepared by the small grain size of the target has better morphology and lower roughness. Lastly, magnetic hysteresis loops and ferromagnetic resonance measurements further shown that a good microstructure and fine grain size of target facilitated the growth of film with greater magnetic properties. Consequently, YIG film deposited by 1.0 mu m-target has magnetic properties with a high saturation magnetization of 155 emu/cm(3), a low saturation magnetic field of 1077 Oe, and low ferromagnetic resonance linewidth of 42 Oe.