LAUSR

In the magneto-optical devices and sensors using the Faraday effect, maintaining the transmitted light intensity of a Faraday element is a key issue. A granular film with ferromagnetic fine metals dispersed in an insulator matrix has been expected to have both high transmittance and large Faraday effect. In this paper, we fabricated the Co–MgF2 granular film prepared by co-evaporation and investigated the effect of substrate heating temperature during co-evaporation and post-annealing on the transmittance and the Faraday rotation of the granular film. The Co–MgF2 granular film deposited at high substrate temperature was exhibited like a ferromagnetic behavior and high transmittance. Also, we found that the figure of merit [deg./dB], which was defined as a ratio of a Faraday rotation angle and decay of the transmitted light, was improved by post-annealing.