Effect of Bi/In co-doing on the Gilbert damping and Faraday rotation of Tm3Fe5O12 film

Rare-earth iron garnet materials are applied extensively in magnetic devices and magneto-optical isolators owing to their superior properties. This Letter presents a detailed investigation of the Gilbert damping and Faraday rotation of Bi/In-doped Tm3Fe5O12 (Bi/In:TmIG) films on SGGG (111) substrates. An increase in indium doping concentration caused the saturation magnetization to rise, and the coercive force decreased along the in-plane magnetization direction. This was accompanied by concurrent variations in the Faraday rotation angle and temperature coefficient. The Gilbert damping factor and ferromagnetic resonance linewidth of the BiTmIn0.5IG sample dropped to 7.51 × 10−3 and 16 Oe at 3 GHz, respectively. In3+ doping affects the crystal structure and magnetic properties of Bi-doped TmIG, in addition to the coupling interactions between Fe3+ ions at the a- and d-sites, respectively. The low damping factor with narrow resonance linewidth has promising potential for the further application of TmIG in magnetron devices and magneto-optical devices.