Tunable ferroelectricity in artificial tri-layer superlattices comprised of non-ferroic components

Abstract

Heterostructured material systems devoid of ferroic components are presumed not to display ordering associated with ferroelectricity. In heterostructures composed of transition metal oxides, however, the disruption introduced by an interface can affect the balance of the competing interactions among electronic spins, charges and orbitals. This has led to the emergence of properties absent in the original building blocks of a heterostructure, including metallicity, magnetism and superconductivity. Here we report the discovery of ferroelectricity in artificial tri-layer superlattices consisting solely of non-ferroelectric ndmno 3 /srmno 3 / Lamno 3 layers. Ferroelectricity was observed below 40 K exhibiting strong tunability by superlattice periodicity. Furthermore, magnetoelectric coupling resulted in 150% magnetic modulation of the polarization. Density functional calculations indicate that broken space inversion symmetry and mixed valency, because of cationic asymmetry and interfacial polar discontinuity, respectively, give rise to the observed behaviour. our results demonstrate the engineering of asymmetric layered structures with emergent ferroelectric and magnetic field tunable functions distinct from that of normal devices, for which the components are typically ferroelectrics.

Strain engineering induced interfacial self-assembly and intrinsic exchange bias in a manganite perovskite film

“…Efforts are increasingly shifting to artificially constructed heterointerfaces between different complex oxides, accompanied by the observation of numerous fascinating phenomena, high-mobility conductivity45, exchange bias67, and ferroelectricity enhancement89, etc. Among these oxide systems, the technological importance of magnetic tunnel junctions1011 and spin injectors12 as potential applications of magnetically active mixed valence manganites, have continuously triggered extensive research.…”

Magnetoelectric coupling across the interface of multiferroic nanocomposites

“…In 2012, Rogdakis et al [78] reported that ferroelectricity emerged in non-ferroelectric NdMnO 3 (NMO)/SMO/LMO artificial tri-layer nanostructures. Both LMO and NMO are A-type antiferromagnets with Mn 3+ ions, whereas SMO is a G-type antiferromagnet with Mn 4+ ions [79−81].…”

First-principles study on the phase diagram and multiferroic properties of (SrCoO3)1/(SrTiO3)1 superlattices

“…Furthermore, interface mediated strain effectively couples the physical properties of their constituents so that the cross controls of constituent properties can be realized. In the recent studies on superlattice structures, the improper ferroelectric effect was found in PbTiO 3 /SrTiO 3 superlattices18 and a large magnetoelectric coupling was also observed in nonferroelectric NdMnO 3 /SrMnO 3 /LaMnO 3 superlattices19. To shed further insight of interface effect on material properties, we have studied, in this Report, the electronic and magnetic properties of (SrCoO 3 ) 1 /(SrTiO 3 ) 1 superlattice (made of SrCoO 3 and SrTiO 3 layers of one cubic-cell thick, SCO/STO).…”

“…Since epitaxial strain plays such an important role in tuning material properties, combining crystals with similar structures but complementary properties into superlattices can be a good option1819. One expects that the resultant materials might combine the characteristics of their constituents.…”