Microwave Magnetoelectric Effects in Single Crystal Bilayers of Yttrium Iron Garnet and Lead Magnesium Niobate-Lead Titanate

TL;DR

This study demonstrates microwave magnetoelectric interactions in single crystal bilayers of YIG and PMN-PT, revealing strong coupling effects and their dependence on magnetic field orientation and film thickness.

Contribution

First experimental observation and theoretical modeling of microwave magnetoelectric effects in single crystal ferromagnetic-piezoelectric bilayers.

Findings

ME coupling is 1-5.4 Oe cm/kOe, stronger than in polycrystalline composites.

Coupling is higher for out-of-plane magnetic fields.

Theoretical estimates agree with experimental data.

Abstract

The first observation of microwave magnetoelectric (ME) interactions through ferromagnetic resonance (FMR) in bilayers of single crystal ferromagnetic-piezoelectric oxides and a theoretical model for the effect are presented. An electric field E produces a mechanical deformation in the piezoelectric phase, resulting in a shift dHE in the resonance field for the ferromagnet. The strength of ME coupling is obtained from data on dHE vs E. Studies were performed at 9.3 GHz on bilayers of (111) yttrium iron garnet (YIG) films and (001) lead magnesium niobate-lead titanate (PMN-PT). The samples were positioned outside a TE102-reflection type cavity. Resonance profiles were obtained for E = 0-8 kV/cm for both in-plane and out-of-plane magnetic fields H. Important results are as follows. (i) The ME coupling in the bilayers is an order of magnitude stronger than in polycrystalline composites and is in the range 1-5.4 Oe cm/kOe, depending on the YIG film thickness. (ii) The coupling strength is dependent on the magnetic field orientation and is higher for out-of-plane H than for in-plane H. (iii) Estimated ME constant and its dependence on volume ratio for the two phases are in good agreement with the data.