Faraday rotation, ferromagnetism, and optical properties in Fe-doped BaTiO3

Abstract

The structural, magneto-optical, optical, and magnetic properties of BaTi1−xFexO3 films grown by pulsed laser deposition onto MgO (100) have been investigated for Fe content, x=0.15, 0.2, 0.3, and 0.5. Saturation Faraday rotation varies from 0.033deg∕μm for x=0.2 to 0.109deg∕μm for x=0.5 at a 1.55-μm wavelength, with corresponding saturation magnetizations of 11.3emu∕cm3 and 18.3emu∕cm3. The optical absorption drops with a reduction in iron content and the BaTi0.85Fe0.15O3 sample has an optical absorption of 1.9dB∕mm. The magneto-optic figure of merit, which is the ratio of Faraday rotation to absorption, peaks at x=0.2 among the samples considered. The magnetic properties are interpreted in terms of the electronic structure of Fe4+ ions, and their exchange coupling with Fe3+ ions associated with oxygen vacancies.