LAUSR

DOI: 10.1002/aelm.201800663 permits the manipulation of magnetism by electric field instead of magnetic field or electric current. Thus, multiferroic materials that couple ferromagnetic and ferroelectric order have drawn considerable interest. Room temperature, singlephase multiferroic materials, however, are still rare, and the converse ME effects are typically small.[4,5] Strain-mediated ME coupling between ferromagnetic (FM) and ferroelectric (FE) heterostructures that serve as an alternative approach to realize electric-field controlled magnetism at room temperature have been intensively investigated recently.[6–8] In these materials, the electric-field induced piezostrain in the FE layer induces an effective magnetic anisotropy in FM layer.[9–11] Converse ME effect studies usually focus on magnetic metals. For instance, Zhang et al. reported the nonvolatile tuning of magnetization in Co40Fe40B20/Pb (Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) structures,[12] while Liu et al. reported the nonvolatile tuning of ferromagnetic resonance (FMR) of the magnetically soft CoFeB alloy using ferroelectric domain switching of PMN-PT substrates.[13] Meanwhile, increasing attention has focused on magnetic insulators, where a pure spin current can transport with no accompanying charge carriers.[14] With the absence of Joule heating, magnetic insulators have great potential in ultralow power information technologies.[15,16] Experimentally, magnon-based logic gates and transistors have been realized.[17–19] Among various magnetic insulators, yttrium iron garnet (Y3Fe5O12 (YIG)), has attracted considerable attention due to its large bandgap, ultralow damping, weak anisotropy, and high Curie temperature.[20,21] In addition to its indispensable contribution to microwave devices, YIG has experienced a resurgence of interest from the spintronics community. YIG provides a perfect platform for pure spin current related study, including spin pumping,[22–24] spin Seebeck effect,[25,26] and spin torque oscillators,[27] due to its low loss and long diffusion length for spin currents.[21] However, high quality YIG thin films generally can only be obtained on gallium gadolinium garnet (GGG) substrates, to which it has a closely matched lattice constant.[28] YIG film growth on FE substrates is still rare due to the large lattice mismatch and high annealing temperature required for YIG film crystallization. Thus, in YIG-based Electric-field-controlled magnetism is of importance in realizing energy efficient, dense and fast information storage and processing. Strain-mediated converse magneto-electric (ME) coupling between ferromagnetic and ferroelectric heterostructure shows promise for realizing electric-controlled magnetism at room temperature and is attracting a number of recent investigations. However, such ME-effect studies have mainly focus on magnetic metals. In this work, high quality yttrium iron garnet (Y3Fe5O12 (YIG)) films are deposited directly onto (100)-oriented single-crystal Pb (Mg1/3Nb2/3)0.7Ti0.3O3 (PMNPT) substrates by means of magnetron sputtering. The electric-field-induced polarization switching and lattice strain in the PMN-PT substrate results in two distinct magnetization states in the YIG film that are nonvolatile and electrically reversible. Because of the direct contact between the YIG and the PMN-PT substrate, an efficient ME coupling and an almost 90° rotation of the easy axis of the YIG film can be realized. Furthermore, the electric-field-controlled hysteresis loop-like ferromagnetic resonance field shifts and spin pumping signals are observed in Pt/YIG/PMN-PT heterostructures. Thus, the obstacle is overcome via growing high-quality YIG thin films directly onto PMN-PT substrates and an efficient manipulation of magnetism and pure spin current transport by electric field is thereby realized. These findings are instructive for future low-power magnetic insulator-based spintronic devices.