Enhanced Tunneling Magnetoresistance Effect via Ferroelectric Control of Interface Electronic/Magnetic Reconstructions

Xiao Chi; Rui Guo; Juxia Xiong; Lizhu Ren; Xinwen Peng; Beng Kang Tay; Jingsheng Chen

doi:10.1021/acsami.1c15836

Enhanced Tunneling Magnetoresistance Effect via Ferroelectric Control of Interface Electronic/Magnetic Reconstructions

ACS Appl Mater Interfaces. 2021 Dec 1;13(47):56638-56644. doi: 10.1021/acsami.1c15836. Epub 2021 Nov 17.

Authors

Xiao Chi¹, Rui Guo^{2

3

4}, Juxia Xiong⁵, Lizhu Ren⁶, Xinwen Peng¹, Beng Kang Tay^{3

4}, Jingsheng Chen²

Affiliations

¹ State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510641, China.
² Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore.
³ Centre for Micro- and Nano-Electronics (CMNE), School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
⁴ UMI 3288 CINTRA (CNRS-NTU-THALES Research Alliances), Nanyang Technological University, Research Techno Plaza, 50 Nanyang Drive, 637553 Singapore.
⁵ School of Environment and Energy, South China University of Technology, Guangzhou 510006, P.R. China.
⁶ Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117583 Singapore.

PMID: 34786928
DOI: 10.1021/acsami.1c15836

Abstract

Magnetic tunnel junctions (MTJs) with tunable tunneling magnetoresistances (TMR) have already been proven to have great potential for spintronics. Especially, when ferroelectric materials are used as insulating barriers, more novel functions of MTJs can be realized due to interface magnetoelectric coupling. Here, we demonstrate a very large ferroelectric modulation of TMR (as high as 570% in low-resistance state) in the ferroelectric/magnetic La_0.5Sr_0.5MnO₃/BaTiO₃ (LSMO/BTO) junctions and find robust interfacial electronic and magnetic reconstructions via ferroelectric polarization switching. Through electrical, magnetic, and optical measurements combined with X-ray absorption and magnetic circular dichroism, we reveal that the interfacial electronic and magnetic (ferromagnetic/antiferromagnetic phase transition) reconstructions originate from strong electromagnetic coupling between BTO and LSMO at the interface and are driven by the modulation of hole/electron doping at the interface of LSMO/BTO through ferroelectric polarization switching. As a result, the ferroelectrically controlled interface barrier height and width and spin filter effect enable a giant electrical modulation of TMR. Our results shed new light on the intrinsic mechanisms governing magnetoelectric coupling and offering a new route to enhance magnetoelectric coupling for spin control in spintronic devices.

Keywords: X-ray absorption; X-ray magnetic circular dichroism; interface electronic/magnetic reconstruction; magnetic tunnel junctions; magnetoresistance.