  Voltage modulation of yttrium iron garnet (YIG) with compactness, high speed
response, energy efficiency and both practical/theoretical siginificances can
be widely applied to various YIG based spintronics such as spin Hall, spin
pumping, spin Seeback effects. Here we initial an ionic modulation of
interfacial magnetism process on YIG/Pt bilayer heterostructures, where the Pt
capping would influence the ferromagnetic (FMR) field position significantly,
and realize a significant magnetism enhancement in bilayer system. A large
voltage induced FMR field shifts of 690 Oe has been achieved in YIG (13 nm)/Pt
(3 nm) multilayer heterostructures under a small voltage bias of 4.5 V. The
remarkable ME tunability comes from voltage induced extra FM ordering in Pt
metal layer near the Pt/YIG interface. The first-principle theoretical
simulation reveal that the electrostatic doping induced Pt5+ ions have strong
magnetic ordering due to uncompensated d orbit electrons. The large voltage
control of FMR change pave a foundation towards novel voltage tunable YIG based
spintronics.
