Observation of Enhanced Faraday Effect in Eu-Doped Ce:YIG Thin Films

Abstract

Ce:YIG thin films are taken as an ideal candidate for magneto-optical devices with giant Faraday effect in the near-infrared range, but it is hindered by a limited Ce3+/Ce4+ ratio and a high saturation driving field. To address this issue, Eu doping can increase the Faraday rotation angle by ∼ 40% to 1.315 × 104 deg/cm and decrease the saturation driving field by ∼ 38% to 1.17 kOe in Eu0.75Ce1Y1.25Fe5O12 compared to Ce1Y2Fe5O12 pristine. The mechanism is attributed to the conversion of Ce4+ to Ce3+ and the weakening of ferrimagnetism by Eu doping. This work not only provides strategies for improving Ce3+/Ce4+ ratio in Ce:YIG, but also develops (Eu,Ce):YIG with a promising Faraday rotation angle for magneto-optical devices.