The Measurement of Magnetostriction Constants by Means of Ferrimagnetic Resonance

A ferrimagnetic resonance field shift is observed when an external load is applied to a spherical specimen of YIG single crystal. The relationship between the shift δ H and the magnetostriction constant λ is given by λ=(2/3)δ H · F M 0 /σ 0 , where M 0 is the saturation magnetization, σ 0 the average stress in the equatorial cross-section of the specimen and F a proportionality factor for non-uniform stress. Neglecting dipolar interactions, the numerical values of F are computed as a function of Poisson's ratio and the ratio of the shift to the linewidth. The shifts of the resonance field of YIG with different linewidth are found to show a good linear relationship with σ 0 / F . The values obtained for λ 100 and λ 111 of YIG at room temperatures are in complete agreement with the values given by the strain gauge technique.