Minimal domains for maximum energy Dielectric capacitors are important electronic components that can store energy, at least for a short period of time. Pan et al . used phase-field simulations to help determine the right combination of bismuth iron oxide, barium titanium oxide, and samarium doping that is likely to generate a material with excellent dielectric properties (see the Perspective by Chu). The simulations guide a set of experimental measurements showing this system can produce a very high-energy storage by breaking down polar domains to the nanometer scale. These materials could be useful for high-power applications and to suppress failure. —BG
The control of material interfaces at the atomic level has led to novel interfacial properties and functionalities. In particular, the study of polar discontinuities at interfaces between complex oxides lies at the frontier of modern condensed matter research. Here we employ a combination of experimental measurements and theoretical calculations to demonstrate the control of a bulk property, namely ferroelectric polarization, of a heteroepitaxial bilayer by precise atomic-scale interface engineering. More specifically, the control is achieved by exploiting the interfacial valence mismatch to influence the electrostatic potential step across the interface, which manifests itself as the biased-voltage in ferroelectric hysteresis loops and determines the ferroelectric state. A broad study of diverse systems comprising different ferroelectrics and conducting perovskite underlayers extends the generality of this phenomenon.complex oxide | heterostructure | interface physics | electronic reconstruction | polar discontinuity O ver the past few years, precisely constructed, atomically sharp perovskite oxide heterointerfaces have become focal points for condensed-matter-physics and materials science research (1-5). The incorporation and reconstruction of spin (6, 7), charge (8-10), and orbital (11) degrees of freedom across the heterointerfaces have led to novel electronic properties that are different from those inherent to the individual components. For example, pioneering work on the LaAlO 3 and SrTiO 3 (STO) heterostructures has revealed a nontrivial two-dimensional electron gas (2DEG) (10,12,13) at the interface, which also exhibits magnetic (14) and even superconductivity properties (15) that are induced by the polar discontinuity (16) (valence mismatch) across the interface.Motivated by this, research nowadays is primarily focused on probing and understanding the novel interfacial phenomena observed in complex-oxide heterostructures. However, the focus on interfacial properties sidesteps possible macroscopic implications of the interfacial atomic-scale control on the broad range of properties that are present in bulk complex oxides. On the other hand, in the semiconductor industry, atomic-scale interface engineering has long been used to improve the performance of devices through control of the threshold voltage (17), channel carrier mobility (18), Schottky barrier height (19), and so on. This forms the fundamental premise for this work: Can we control the bulk properties of a heterostructured system through the emergent state of matter at the interface? Such an approach could be particularly intriguing if one of the layers is highly polar and electrically switchable, i.e., ferroelectric in nature. Because functional ferroelectric systems, such as the nonvolatile memory (20), ferroelectric field effect transistor (21, 22), ferroelectric tunnel junction (23-27), and switching photo-diode (28), are strongly correlated with the interface electronic structures, it is of great importance to study how the interface atom...
We report the creation of a multiferroic field effect device with a BiFeO(3) (BFO) (antiferromagnetic-ferroelectric) gate dielectric and a La(0.7)Sr(0.3)MnO(3) (LSMO) (ferromagnetic) conducting channel that exhibits direct, bipolar electrical control of exchange bias. We show that exchange bias is reversibly switched between two stable states with opposite exchange bias polarities upon ferroelectric poling of the BFO. No field cooling, temperature cycling, or additional applied magnetic or electric field beyond the initial BFO polarization is needed for this bipolar modulation effect. Based on these results and the current understanding of exchange bias, we propose a model to explain the control of exchange bias. In this model the coupled antiferromagnetic-ferroelectric order in BFO along with the modulation of interfacial exchange interactions due to ionic displacement of Fe(3+) in BFO relative to Mn(3+/4+) in LSMO cause bipolar modulation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.