Magnetoelectric phase transition driven by interfacial-engineered Dzyaloshinskii-Moriya interaction

Xin Liu,Mei Wu,Young Sun,Yinhua Tian,Nan Chen ,Yuanwei Sun,Youguo Shi,Jingdi Lu,Peng Gao,Nian X Sun ,Su-Peng Kou ,Wenlei Song ,Ka Shen,Peipei Lu,Ying Yang,Yuben Yang,Dayu Yan,Jing Wang,Guozhi Chai,Jinxing Zhang

doi:10.1038/s41467-021-25759-1

Abstract

Strongly correlated oxides with a broken symmetry could exhibit various phase transitions, such as superconductivity, magnetism and ferroelectricity. Construction of superlattices using these materials is effective to design crystal symmetries at atomic scale for emergent orderings and phases. Here, antiferromagnetic Ruddlesden-Popper Sr2IrO4 and perovskite paraelectric (ferroelectric) SrTiO3 (BaTiO3) are selected to epitaxially fabricate superlattices for symmetry engineering. An emergent magnetoelectric phase transition is achieved in Sr2IrO4/SrTiO3 superlattices with artificially designed ferroelectricity, where an observable interfacial Dzyaloshinskii-Moriya interaction driven by non-equivalent interface is considered as the microscopic origin. By further increasing the polarization namely interfacial Dzyaloshinskii-Moriya interaction via replacing SrTiO3 with BaTiO3, the transition temperature can be enhanced from 46 K to 203 K, accompanying a pronounced magnetoelectric coefficient of ~495 mV/cm·Oe. This interfacial engineering of Dzyaloshinskii-Moriya interaction provides a strategy to design quantum phases and orderings in correlated electron systems.

Highlights

Correlated oxides with a broken symmetry could exhibit various phase transitions, such as superconductivity, magnetism and ferroelectricity
It is highly desirable to design a controllable ME phase based on symmetry engineering and the interplay of quantum orderings in artificial superlattices, which is absent or rare in natural bulk crystals[28,31,35]
Dzyaloshinskii–Moriya interaction (DMI) has been considered to be an effective energy to generate spiral spin textures via antisymmetric magnetic couplings in non-centrosymmetricferromagnets with spin–orbit coupling, which bridges the timereversal symmetry with space-inversion symmetry[36,37,38]

Summary

Introduction

Correlated oxides with a broken symmetry could exhibit various phase transitions, such as superconductivity, magnetism and ferroelectricity. Emergent order parameters or phase transitions with ME effects may be driven by simultaneous manipulation of spin (M), polar (P), even effective electric (E), or magnetic fields (H) via engineering the DMI at atomic scale[39]. The magnetic system with strong spin–orbit coupling and polar structure in the inversion-symmetry-broken superlattices by combining SIO and STO can be regarded as potential ingredients to the DMI34,35.

Results

Conclusion