Faraday effect of oxidized permalloy nanofilms upon hydrogenation

Spectra of oxidized permalloy nanofilms were studied when subjecting them to hydrogenation. In contrast to the usual change in transmittance (optical constants) inherent to gasochromic metal oxides, we demonstrate changes in optical gyrotropy of oxidized permalloy/platinum bilayers. Hydrogenation of the bilayers caused changes in both the spectral shape and magnitude of the wavelength dependence of the Faraday rotation. The observed transformations were proved to have the nonreciprocal nature, thus demonstrating “gasogyrochromism” of the magnetic oxides under study.