Abstract
Magnetic tunnel junctions (MTJs) are key components of spintronic devices, such as magnetic random-access memories. Normally, MTJs consist of two ferromagnetic (FM) electrodes separated by an insulating barrier layer. Their key functional property is tunneling magnetoresistance (TMR), which is a change in MTJ's resistance when magnetization of the two electrodes alters from parallel to antiparallel. Here, we demonstrate that TMR can occur in MTJs with a single FM electrode, provided that the counterelectrode is an antiferromagnetic (AFM) metal that supports a spin-split band structure and/or a Néel spin current. Using as a representative example of such antiferromagnet and as a FM metal, we design all-rutile MTJs to reveal a nonvanishing TMR. Our first-principles calculations predict that magnetization reversal in significantly changes conductance of the MTJs stacked in the (110) or (001) planes. The predicted giant TMR effect of about 1000% in the (110)-oriented MTJs stems from spin-dependent conduction channels in (110) and (110), whose matching alters with magnetization orientation, while TMR in the (001)-oriented MTJs originates from the Néel spin currents and different effective barrier thickness for two magnetic sublattices that can be engineered by the alternating deposition of and monolayers. Our results demonstrate a possibility of a sizable TMR in MTJs with a single FM electrode and offer a practical test for using the antiferromagnet in functional spintronic devices.
- Received 8 October 2023
- Accepted 12 April 2024
DOI:https://doi.org/10.1103/PhysRevB.109.174407
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