Electric-field tunable rotation of optical mode ferromagnetic resonance in FeCoB/Ru/FeCoB/PMN-PT multilayers

Abstract

FeCoB/Ru/FeCoB trilayers with a uniaxial magnetic anisotropy were deposited on (011)-cut lead magnesium niobate-lead titanate (PMN-PT) single crystal ferroelectric substrates using a compositional gradient sputtering (CGS) method. Ultrahigh optical mode resonance frequencies from 11.76 to 18.96 GHz at zero magnetic field were achieved due to the strong interlayer exchange coupling between FeCoB films through Ru spacer. In this study, two orthogonal magnetic anisotropic fields (one is CGS induced anisotropy field HKCGS and the other is the piezoelectric stress-induced anisotropy field HKME) were set to realize electric-field (E-field) controlled switch of magnetic moment configuration through their competition. As a result, the optical mode resonance intensity can make reversible 90° rotation under applied E-field, while the advantages of ultrahigh frequency optical mode resonance in trilayers are still maintained because the interlayer exchange coupling is not destroyed by magnetoelectric coupling. The ultrahigh resonance frequency and E-field tunable and reversible FMR rotation in these trilayers provide a potential route to guide microwave flow in multifunctional microwave and spintronic devices.