Giant and Tunneling Magnetoresistance in Unconventional Collinear Antiferromagnets with Nonrelativistic Spin-Momentum Coupling

• Published in: Physical review. X Vol. 12; no. 1; p. 011028
• Main Authors: Šmejkal, Libor, Hellenes, Anna Birk, González-Hernández, Rafael, Sinova, Jairo, Jungwirth, Tomas
• Format: Journal Article
• Language: English
• Published: College Park American Physical Society 01-02-2022
• Subjects: Antiferromagnetism; Couplings; Electrode polarization; Electrodes; Energy gap; Ferromagnetic materials; First principles; Giant magnetoresistance; Magnetization; Magnetoresistivity; Momentum; Multilayers; Polarization (spin alignment); Spintronics; Transport phenomena
• ISSN: 2160-3308; 2160-3308
• DOI: 10.1103/PhysRevX.12.011028

Giant and tunneling magnetoresistance are physical phenomena used for reading information in commercial spintronic devices. The effects rely on a conserved spin current passing between a reference and a sensing ferromagnetic electrode in a multilayer structure. Recently, we have proposed that these fundamental spintronic effects can be realized in unconventional collinear antiferromagnets with nonrelativistic alternating spin-momentum coupling. Here, we elaborate on the proposal by presenting archetype model mechanisms for the giant and tunneling magnetoresistance effects in multilayers composed of these unconventional collinear antiferromagnets. The models are based, respectively, on anisotropic and valley-dependent forms of the alternating spin-momentum coupling. Using first-principles calculations, we link these model mechanisms to real materials and predict an approximately 100% scale for the effects. We point out that, besides the giant or tunneling magnetoresistance detection, the alternating spin-momentum coupling can allow for magnetic excitation by the spin-transfer torque.