Circularly Polarized Light-Induced Magnetization Reversal in Bi,Ga-Substituted Magnetic Garnet Films

Abstract All-optical magnetization switching (AOS) in magneto-optical materials is promising phenomena for applications such as high-speed optical modulation technology, as it allows for magnetization reversal using only ultrashort laser pulses. We report on AOS induced by circularly polarized light in Bi,Ga-substituted magnetic garnet, Bi 2.5 R 0.5 Fe 4 GaO 12 (R = Eu, Nd and Y), thin films prepared by the metal-organic decomposition method, which possess both large Faraday effect and perpendicular magnetic anisotropy. The experiments for circularly polarized light-induced magnetization reversal were performed using laser pulses with a wavelength of 514 nm and a pulse width of 230 fs. Helicity-dependent ring-shaped magnetic domains were formed around demagnetized domains for all samples, when approximately 200 pulses were cumulatively irradiated onto a single spot on the samples.