Extraordinary enhancement of magneto-optical Faraday rotation angle in Bi-YIG/Pt/glass prepared by metal organic decomposition method

We achieve the extraordinary enhancement of magneto-optical Faraday rotation angle for bismuth-substituted yttrium iron garnet (Bi-YIG) using the metal-organic decomposition method, by introducing a Pt underlayer. The Faraday rotation angle reaches -25°/μm for the sample with a Pt thickness of 45 nm, which is 5 times higher than that of a bare thin film, setting a new record value for chemically synthesized Bi-YIG films. Through X-ray diffractometer, vibrating sample magnetometer, and energy dispersive X-ray spectroscopy analyses, we found that this enhancement is attributed to improved crystallinity, saturation magnetization, and the formation of a PtBi alloy phase, facilitated by Pt acting as an absorbing layer of Bi. We propose that the Bi-YIG/Pt film structure, with an optimum thickness of Pt underlayer, shows great promise for applications in various magneto-optical devices that require high detection sensitivity for small signals. [Display omitted]