Quantitative Study on Current-Induced Effect in an Antiferromagnet Insulator/Pt Bilayer Film

Abstract

Electrical control and detection of magnetic ordering inside antiferromagnets has attracted considerable interests, for the potential advantages in operating speed and device densities.In contrast to ferromagnets, where the current-induced torque on magnetic moments can be analyzed via comparison with magnetic field's influence, the quantitative investigation on the spin torque mechanism in antiferromagnets represents a greater challenge, due to the lack of a convenient, independent method for controlling Né el vectors. Here by utilizing an antiferromagnetic insulator with Dzyaloshinskii-Moriya interaction, α-Fe2O3, we show that the Né el vector can be easily controlled with the application of a moderate external magnetic field, which can be further used to examine the current-induced magnetic dynamics. We find that in this antiferromagnetic insulator, current-induced magnetoresistance change can be complicated by resistive switching that does not have a magnetic origin. By excluding nonmagnetic switching and comparing the current-induced and field-induced Né el vector tilting, we reveal the important role of magnetoelastic effect in current-induced dynamics of this antiferromagnet. The nature and magnitude of magnetoelastic effect is further determined and compared with possible spin orbit torque influences.

Electric‐Field‐Controlled Antiferromagnetic Spintronic Devices

“…Furthermore, in this work, the resistance difference between high‐ and low‐resistance states is not very stable upon electrical cycling, which needs to be largely improved. On the other hand, the “saw‐tooth” shaped resistance variation in this work may not be fully induced by the antiferromagnetic spin switching as the recent experimental works47,48 found that the Joule heating itself can result in a similar resistance variation.…”

“…Despite the above intriguing resistance switching induced by external electrical currents, which have mainly contributed to electrical switching of Néel vectors in antiferromagnets, there are other reports that emphasize nonspin–orbit torque origins47 or the absence of the electrical switching of Néel vectors48 in antiferromagnets. For example, the magnetoelastic effect could be important,47 and Joule heating could be significant in current‐switched antiferromagnetic spintronic devices 48.…”

“…Despite the above intriguing resistance switching induced by external electrical currents, which have mainly contributed to electrical switching of Néel vectors in antiferromagnets, there are other reports that emphasize nonspin–orbit torque origins47 or the absence of the electrical switching of Néel vectors48 in antiferromagnets. For example, the magnetoelastic effect could be important,47 and Joule heating could be significant in current‐switched antiferromagnetic spintronic devices 48. A possible useful approach for determining whether the current switching effect is intrinsic or extrinsic is to use the spin‐flop transition triggered by external magnetic fields, which for sure can manipulate the AFM spins, to examine the effect of spin structure change on Hall resistance and subsequently compare the current switching of Hall resistance.…”

Demonstration of Spin Current Switch across Ferro‐Antiferromagnetic Transition

“…Under a high writing current density of 10 7 A cm −2 , intense Joule heat causes irreversible changes in the device due to electromigration and magnetoelastic artifacts, which overwhelms the spin-dependent signal. [1][2][3][4] On the other hand, utilizing AFM as a spin transmission modulator is more promising. [5] For instance, it has been shown that spin current excited by thermal gradient or microwave on a ferrimagnetic insulator, usually Y 3 Fe 5 O 12 (YIG), can be significantly enhanced through the insertion of an AFM insulator layer, such as NiO and CoO.…”

Magneto-Seebeck microscopy of domain switching in collinear antiferromagnet CuMnAs

“…The aim of these microscopies is to elucidate physical mechanisms of the switching which, e.g., in CuM-nAs have been associated with the Néel vector reorientation induced by the NSOT, and with electrical or optical pulse-induced quenching into nano-fragmented domain states of the antiferromagnet 20,21 . The microscopies are also essential for disentangling potential parasitic non-magnetic contributions to the resistive switching signals, as reported in metal/antiferromagnetic-insulator bilayers 19,[22][23][24][25][26] .…”