Enhanced Faraday rotation in garnet films and multilayers

Abstract

AbstractFilms were prepared by pulsed laser deposition. We investigated or measured crystallinity, morphology, film-substrate interface, cracks, roughness, composition, magnetic coercivity, refractive index and extinction coefficient, and magneto-optical Faraday rotation (FR) and ellipticity. The investigations were partly performed on selected samples, and partly on two series of films on different substrates and of different thicknesses. BIG films were successfully tested for the application of magneto-optical visualization. The effect of annealing in oxygen atmosphere was also investigated - very careful annealing can increase FR by up to 20%.Periodical BIG-YIG multilayers with up to 25 single layers were designed and prepared with the purpose to enhance FR at a selected wavelength. A central BIG layer was introduced as defect layer into this one-dimensional magneto-optical photonic crystal (MOPC) and generated resonances in optical transmittance and FR at a chosen design wavelength. In a 17-layer structure, at the wavelength of 748 nm, FR was increased from–2.6 deg/μm to –6.3 deg/μm at a small reduction in transmittance from 69% to 58% as compared to a single-layer BIG film of equivalent thickness. In contrast to thick BIG films, the MOPCs did not crack. We were first to report preparation of all-garnet MOPCs and second to experimentally demonstrate the MOPC principle in magneto-optical garnets.