Temperature Dependence of Magneto-Optical Effects in Nickel Thin Films

The Faraday rotation and magnetic circular dichroism in thin films of ferromagnetic nickel are measured with He-Ne laser light (λ=632.8 nm) up to a temperature slightly above the Curie point T c . The results near T c can satisfactorily be analyzed on the assumption that the magneto-optical parameters Q 1 and Q 2 are proportional to the magnetization, regardless of whether the magnetization is spontaneous or induced by applied fields. Slight deviations from the proportionality are found at lower temperatures; temperature coefficients of both Q 1 and Q 2 are somewhat larger than those of the spontaneous magnetization.