Light-induced giant and persistent changes in the converse magnetoelastic effects in Ni/BaTiO3 multiferroic heterostructure (original) (raw)
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Physical Review B
We present a study of the control of electric field induced strain on the magnetic and electrical transport properties in a magnetoelastically coupled artificial multiferroic Fe 3 O 4 /BaTiO 3 heterostructure. In this Fe 3 O 4 /BaTiO 3 heterostructure, the Fe 3 O 4 thin film is epitaxially grown in the form of bilateral domains, analogous to a-c stripe domains of the underlying BaTiO 3 (001) substrate. By in situ electric field dependent magnetization measurements, we demonstrate the extrinsic control of the magnetic anisotropy and the characteristic Verwey metal-insulator transition of the epitaxial Fe 3 O 4 thin film in a wide temperature range between 20-300 K, via strain mediated converse magnetoelectric coupling. In addition, we observe strain induced modulations in the magnetic and electrical transport properties of the Fe 3 O 4 thin film across the thermally driven intrinsic ferroelectric and structural phase transitions of the BaTiO 3 substrate. In situ electric field dependent Raman measurements reveal that the electric field does not significantly modify the antiphase boundary defects in the Fe 3 O 4 thin film once it is thermodynamically stable after deposition and that the modification of the magnetic properties is mainly caused by strain induced lattice distortions and magnetic anisotropy. These results provide a framework to realize electrical control of the magnetization in a classical highly correlated transition metal oxide.
ACS Nano, 2014
Magnetoelectric oxide heterostructures are proposed active layers for spintronic memory and logic devices, where information is conveyed through spin transport in the solid state. Incomplete theories of the coupling between local strain, charge, and magnetic order have limited their deployment into new information and communication technologies. In this study, we report direct, local measurements of strainand charge-mediated magnetization changes in the La 0.7 Sr 0.3 MnO 3 /PbZr 0.2 Ti 0.8 O 3 system using spatially resolved characterization techniques in both real and reciprocal space.
Voltage control of magnetic single domains in Ni discs on ferroelectric BaTiO3
Journal of Physics D: Applied Physics, 2018
For 1 m-diameter Ni discs on a BaTiO 3 substrate, the local magnetization direction is determined by ferroelectric domain orientation as a consequence of growth strain, such that single-domain discs lie on single ferroelectric domains. On applying a voltage across the substrate, ferroelectric domain switching yields non-volatile magnetization rotations of 90°, while piezoelectric effects that are small and continuous yield non-volatile magnetization reversals that are non-deterministic. This demonstration of magnetization reversal without ferroelectric domain switching implies reduced fatigue, and therefore represents a step towards applications. Ferroelectric and ferromagnetic materials that are coupled via strain or exchange bias show large magnetoelectric effects at room temperature, and have therefore attracted considerable interest since the turn of the century [1-5]. For example, the heterostructures that display these magnetoelectric effects permit an applied electric field to switch individual magnetic domains [6], modify a large in-plane magnetization [7-8], switch a large magnetization from
2014
The pursuit of a universal memory-possessing fast write/read times, nonvolatile and unlimited data endurance, low operating power, low manufacture costs, high bit density, as well as being easily integrable with on-trend complementary metal-oxide semiconductor (CMOS) devices-has reenergized research in the field of multiferroic and magnetoelectric materials. Such materials simultaneously exhibit ferroelectricity and ferromagnetism, and allow for the coupling of the two order parameters, known as magnetoelectric coupling. This coupling is enhanced in magnetostrictive/piezoelectric bilayer systems where applied electrical bias can modify magnetic order via strain-mediation, a mechanism that can reduce the power demands in emerging magnetic random access memory (MRAM) technologies. We have previously investigated this relationship in an Fe 0.7 Ga 0.3 /BaTiO 3 bilayer structure using magnetic contrast imaging techniques with
Physical Review Materials
We investigate the influence of dislocations and twin walls in BaTiO 3 on its ferroelectric response and the resulting effect on the perpendicular magnetic anisotropy (PMA) of a strain-coupled [Co\Ni] n film. A dense twinned structure in conjunction with a high dislocation density significantly reduces the converse piezoelectric effect of BaTiO 3 by hindering the propagation of newly nucleated domains with an applied electric field. This, in turn, results in a modest reduction of the PMA of the ferromagnetic layer. On the other hand, the ferroelectric polarization reorients from [100] to [001] direction in a dislocationfree BaTiO 3 , inducing the maximum achievable in-plane compressive strain of 1.1%. A large fraction of this uniaxial strain is transferred to the magnetoelastically coupled ferromagnetic layers whose magnetization switches to in-plane via the inverse magnetostriction effect. This work reveals the critical role of the interplay between twin walls and dislocations within a ferroelectric substrate in the performance of multiferroic heterostructures and provides insight into the development of highly energy-efficient magnetoelectric devices. Controlling magnetization at small scales with electric fields opens up new prospects for highly energyefficient logic [1,2] and memory devices [3]. Conventionally, magnetization has been electrically controlled via spin-transfer torque [4] and, more recently, by spin-orbit torque [5]. However, both mechanisms use electric currents resulting in significant Ohmic heating losses, leading to low energy efficiency. Voltage control of magnetism arises as a promising alternative to power-consuming current-based approaches. One voltage-controlled system is based on strain-mediated multiferroic heterostructures, where a ferromagnetic _____________________________
We studied in detail the in-plane magnetic properties in heterostructures based on a ferroelectric BaTiO3 overlayer deposited on a ferromagnetic La2/3Sr1/3MnO3 film grown on pseudocubic (001)-oriented SrTiO3, (LaAlO3)0.3(Sr2TaAlO6)0.7 and LaAlO3 substrates. In this configuration, the combination of both functional perovskites constitutes an artificial multiferroic system with potential applications in spintronic devices based on the magnetoelectric effect. We have grown the La2/3Sr1/3MnO3 single layers and BaTiO3/La2/3Sr1/3MnO3 bilayers by pulsed-laser deposition technique. We analyzed the films structurally through X-ray reciprocal space maps, and high-angle annular dark field microscopy; magnetically, via thermal demagnetization curves and in-plane magnetization versus applied magnetic field loops, at room temperature. Our results indicate that the BaTiO3 layer induces an additional strain in the La2/3Sr1/3MnO3 layers close to their common interface. We observed that the presence...
Physical Review Materials, 2021
We study magnetic and magnetotransport properties of an epitaxial interfacial multiferroic system consisting of a ferromagnetic Heusler-alloy Co 2 FeSi and a ferroelectric-oxide BaTiO 3. L2 1-ordered Co 2 FeSi epilayers on BaTiO 3 (001) show an in-plane uniaxial magnetic anisotropy with strong temperature dependence, induced by the presence of the magnetoelastic effect via the spin-orbit interaction at the Co 2 FeSi/BaTiO 3 (001) interface. In the Co 2 FeSi Hall-bar devices, the anisotropic magnetoresistance (AMR) hysteretic curves depending on inplane magnetization reversal processes on the a and c domains of BaTiO 3 (001) are clearly observed at room temperature. Notably, the magnitude of the AMR ratio (%) for Co 2 FeSi Hall-bar devices can be tuned through the a − c domain wall motion of BaTiO 3 (001) by applying electric fields. We propose that the tunable AMR effect is associated with the modulation of the spin-orbit interaction, exchange interaction, and/or the electronic band structure near the Fermi level by applying electric fields in the epitaxial Co 2 FeSi/BaTiO 3 (001) interfacial multiferroic system.