Nonvolatile voltage-controlled magnetization reversal in a spin-valve multiferroic heterostructure

Mengli Liu,Hua Su,Bo Liu,Xiaoli Tang,Hao Meng,Wei Du,Huaiwu Zhang

doi:10.1038/s41427-021-00333-9

Abstract

Pure voltage-controlled magnetism, rather than a spin current or magnetic field, is the goal for next-generation ultralow power consumption spintronic devices. To advance toward this goal, we report a voltage-controlled nonvolatile 90° magnetization rotation and voltage-assisted 180° magnetization reversal in a spin-valve multiferroic heterostructure. Here, a spin valve with a synthetic antiferromagnetic structure was grown on a (110)-cut Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) substrate, in which only the magnetic moment of the free layer can be manipulated by an electric field (E-field) via the strain-mediated magnetoelectric coupling effect. As a result of selecting a specified PMN-PT substrate with defect dipoles, nonvolatile and stable magnetization switching was achieved by using voltage impulses. Accordingly, a giant, reversible and nonvolatile magnetoresistance modulation was achieved without the assistance of a magnetic field. In addition, by adopting a small voltage impulse, the critical magnetic field required for complete 180° magnetization reversal of the free layer can be tremendously reduced. A magnetoresistance ratio as large as that obtained by a magnetic field or spin current under normal conditions is achieved. These results indicate that E-field-assisted energy-efficient in-plane magnetization switching is a feasible strategy. This work is significant to the development of ultralow-power magnetoresistive memory and spintronic devices.

Highlights

Magnetoresistive random access memory (MRAM) is regarded as the most promising advance in nextgeneration information storage technologies[1,2,3]
The giant magnetoresistance (GMR) ratio is approximately 5.5%, and the exchange bias field is above 1000 Oe
The synthetic antiferromagnetic (SAF) structure of CoFe/Ru/CoFe is chosen to produce a large exchange bias field[31], while its magnetization should be fixed without being affected by the converse magnetoelectric (CME) from the PMN-PT substrate

Summary

Introduction

Magnetoresistive random access memory (MRAM) is regarded as the most promising advance in nextgeneration information storage technologies[1,2,3]. It has attractive advantages such as fast operation, high density, nonvolatility, infinite endurance, and low power consumption[4,5]. In typical MRAM devices, the information writing process is carried out with a magnetic field produced by a current[6,7]. Considerable energy consumption overheating are drawbacks encountered during the magnetization switching process. This has hindered the further development of MRAM devices. Increasing attention has been given to spin-transfer torque (STT)

Methods

Results

Conclusion