Influence of photo - excited Ho3+ ions on ferromagnetic resonance in Y3Fe5O12

Abstract The influence of optical laser irradiation on ferromagnetic resonance in single crystal Y 3 Fe 5 O 12 doped by holmium ions has been investigated. At given magnetic field value the change of magnetic resonance parameters takes place, and it leads to the microwave absorption change. When laser impulse is discontinued, the relaxation time of microwave absorption change is 4 ÷ 5 msec. Experimental data analysis shows that the effect is not explained by optical irradiation heating. This connected with transition of the part of Ho 3+ ions to an excited state.