Date of Award

Spring 5-1-2025

Document Type

Thesis

Degree Name

Bachelor of Arts

Department

Physics

First Advisor

Frank Peiris

Abstract

Spectroscopic ellipsometry and the magneto-optical Kerr effect (MOKE) were combined to measure the magneto-optical properties of Y3Fe5O15 (YIG) thin films. By studying the reflected and transmitted electromagnetic waves off of a material, one can completely represent the material with a dielectric tensor. The ellipsometry results showed that the YIG films are semiconductors with a band gap of approximately 2.25 eV. They also showed some defects present especially in the thinner films, demonstrated by a long tail in the lower-energy range of the imaginary part of the dielectric function. The MOKE measurements were performed at two different wavelengths (550 and 632 nm) with both the longitudinal and polar geometries. We were able to measure the Kerr rotation and ellipticity for all samples, and found that the signal was larger in the polar measurements compared to the longitudinal measurements. We found that the Kerr rotation reduces as the thickness of the YIG samples reduces, therefore indicating a decrease in the ferrimagnetic properties of the thinner YIG films. This result is contradictory to published results, and may be a consequence of the sample defects in the films. The ellipsometry results suggested higher defect concentrations in the thinner films, and therefore these samples may have a lower oxygen concentration, which is crucial in producing the magnetic properties of YIG. For the YIG films, from combining both spectroscopic ellipsometry and MOKE, we were able to obtain seven out of the nine elements in the dielectric tensor at 550 nm for all three YIG samples.

Rights Statement

All rights reserved. This copy is provided to the Kenyon Community solely for individual academic use. For any other use, please contact the copyright holder for permission.

Download

Share

COinS