Nonlinear magnetoelectric effects in Y-type hexaferrite microwave resonators

Abstract

The nature of the nonlinear magnetoelectric effect is investigated in platelets of single-crystal Y-type hexaferrite with a collinear ferrimagnetic structure. The effect was observed at room temperature as a shift of 1.1-to-1.4 GHz in the ferromagnetic resonance frequency of Ba2Zn2Fe12O22 (Zn2Y) rectangular resonator with the application of an in-plane DC voltage. The shift amounted to 10%–12% of the central frequency which ranged from 8 to 17 GHz (X and Ku-bands). From the experimental results, we estimated the magnetoelectric modification of effective saturation magnetization and found that it scales almost linearly with the applied DC electric power. A phenomenological model for the nonlinear magnetoelectric effect, which considers the hexaferrite magnetic symmetry, is proposed and qualitatively accounts for the observed dependence of magnetic parameters on input power. It is shown that the resonator can operate as an electrically controlled discrete phase shifter with almost π/4 phase shift and <4 dB insertion losses. These results are of importance for the use of Y-type hexaferrites in electrically tunable planar microwave signal processing devices.