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

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 Eu_0.75Ce₁Y_1.25Fe₅O₁₂ 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.