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Title: Tunneling magnetoresistance in magnetic tunnel junctions with a single ferromagnetic electrode
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 counter electrode is an antiferromagnetic (AFM) metal that supports a spin-split band structure and/or a Néel spin current. Using Ru⁢O2 as a representative example of such antiferromagnet and Cr⁢O2 as a FM metal, we design all-rutile Ru⁢O2/Ti⁢O2/Cr⁢O2 MTJs to reveal a non-vanishing TMR. Our first-principles calculations predict that magnetization reversal in Cr⁢O2 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 Cr⁢O2 (110) and Ru⁢O2 (110), whose matching alters with Cr⁢O2 magnetization orientation, while TMR in the (001)-oriented MTJs originates from the Néel spin currents and different effective Ti⁢O2 barrier thickness for two magnetic sublattices that can be engineered by the alternating deposition of Ti⁢O2 and Cr⁢O2 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 Ru⁢O2 in functional spintronic devices.  more » « less
Award ID(s):
2316665
PAR ID:
10523798
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
American Physical Society
Date Published:
Journal Name:
Physical Review B
Volume:
109
Issue:
17
ISSN:
2469-9950
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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