Giant anisotropic magnetoresistance and nonvolatile memory in canted antiferromagnet Sr2IrO4

Haowen Wang,S L Yuan,Jun-Ming Liu,Shuai Dong,Chengliang Lu,Sang-Wook Cheong,Jun Chen,Yong Liu

doi:10.1038/s41467-019-10299-6

Abstract

Antiferromagnets have been generating intense interest in the spintronics community, owing to their intrinsic appealing properties like zero stray field and ultrafast spin dynamics. While the control of antiferromagnetic (AFM) orders has been realized by various means, applicably appreciated functionalities on the readout side of AFM-based devices are urgently desired. Here, we report the remarkably enhanced anisotropic magnetoresistance (AMR) as giant as ~160% in a simple resistor structure made of AFM Sr2IrO4 without auxiliary reference layer. The underlying mechanism for the giant AMR is an indispensable combination of atomic scale giant-MR-like effect and magnetocrystalline anisotropy energy, which was not accessed earlier. Furthermore, we demonstrate the bistable nonvolatile memory states that can be switched in-situ without the inconvenient heat-assisted procedure, and robustly preserved even at zero magnetic field, due to the modified interlayer coupling by 1% Ga-doping in Sr2IrO4. These findings represent a straightforward step toward the AFM spintronic devices.

Highlights

Antiferromagnets have been generating intense interest in the spintronics community, owing to their intrinsic appealing properties like zero stray field and ultrafast spin dynamics
We have demonstrated giant anisotropic magnetoresistance (AMR) and nonvolatile memory in simple AFM resistors made of Jeff = 1/2 antiferromagnets without auxiliary reference layer
Note that coupling to FM layer would lose the unique merits of antiferromagnets in AFM spintronics devices

Summary

Introduction

Antiferromagnets have been generating intense interest in the spintronics community, owing to their intrinsic appealing properties like zero stray field and ultrafast spin dynamics. We demonstrate the bistable nonvolatile memory states that can be switched in-situ without the inconvenient heat-assisted procedure, and robustly preserved even at zero magnetic field, due to the modified interlayer coupling by 1% Ga-doping in Sr2IrO4 These findings represent a straightforward step toward the AFM spintronic devices. The main obstacle that keeps the AFM materials away from even more extensive applications is the great challenge in detection and manipulation of AFM orders because of their imperviousness to external magnetic field This perception has been largely modified, and the emerging concept of AFM-spintronics has been garnering considerable interest. A number of exotic phenomena, such as spin polarized current and anomalous Hall effect which were assumed to only happen in ferromagnets, were revealed in bulk AFM materials This provides an excellent opportunity to combine the typical spintronics phenomena, i.e., giant or tunneling magnetoresistance (GMR or TMR) with AFM–AMR without expense of structural complexity. The synergy of different types of magneto-transports may lead to unconventional AFM-based functionalities

Methods

Results

Conclusion