Optical and magneto-optical properties of Bi substituted yttrium iron garnets prepared by metal organic decomposition

Abstract

In this work, we present a systematic study of optical and magneto-optical properties of Y 3-x Bi x Fe 5 O 12 thin films with various Bi concentrations (x = 1.5, 2, 2.5, 3) prepared by Metal Organic Decomposition on Gd 3 Ga 5 O 12 (100) substrates. We used magneto-optical spectroscopy and spectroscopic ellipsometry. Spectral dependence of complex refraction indexes obtained from ellipsometric measurements revealed increasing optical absorption with increasing Bi concentrations. Faraday and Kerr magneto-optical spectra measured in the photon energy range from 1.5 to 5.5 eV clearly demonstrated that the increasing Bi concentration enhances the spin-orbit coupling and influences the magnetooptical effect. Using the magneto-optical and ellipsometric experimental data we deduced a spectral dependence of complete permittivity tensor in a wide spectral range. Comparison of obtained results with the results reported on Liquid Phase Epitaxy bulk-like garnets with small Bi concentrations showed agreement and confirmed a high optical and magneto-optical quality of investigated films.

Simultaneous imaging of magnetic field and temperature distributions by magneto optical indicator microscopy

“…This is because of an enhancement of the noise ( N rms ) at λ  = 470 nm, and it can be explained due to the increase of absorption at λ  = 470 nm resulting in a decline of reflected light passed through the Bi-YIG layer. This result is consistent with the previous reports that the Bi-YIG material has a high figure of merit at the green-wavelength light for the magnetic field sensing due to its high transparency at that wavelength16.…”

“…For the Bi-YIG material, the concentration of the bismuth strongly influences the magneto optical properties and the optical absorption of the material161718. In particular, the optical properties strongly depend on the wavelength of the incident light, and therefore, it is critical to find a proper concentration of the bismuth and a wavelength of the probing light maximizing the measurement sensitivity.…”

“…In addition, we note that the absence of the MCD signal of x = 2 MOI at λ  = 470 nm comes from a strong absorption of the blue wavelength light. It is known that for the visible wavelength light, the MCD of Bi-YIG material is maximized around λ  = 500 nm, and it is increased along with an increase of the bismuth concentration161718. Although the increase of bismuth concentration enhances the MCD of the Bi-YIG material, it involves a red shift of the absorption edge that results in a rapid increase of the optical absorption at a short wavelength161718.…”

“…It is known that for the visible wavelength light, the MCD of Bi-YIG material is maximized around λ  = 500 nm, and it is increased along with an increase of the bismuth concentration161718. Although the increase of bismuth concentration enhances the MCD of the Bi-YIG material, it involves a red shift of the absorption edge that results in a rapid increase of the optical absorption at a short wavelength161718. Because the MCD signal depends on the reflected light that has passed through the Bi-YIG thin film, the rapid increase of optical absorption will result in a decline and disappearance of the MCD signal.…”

Development of MO imaging plate for MO color imaging

“…The spectral profiles strongly depended on the film composition and substrate material. However, the spectral profiles could potentially be modeled by optical simulations, if the optical constants including the permittivity tensors are known 22) .…”