CM In the literature: open

Large tunneling magnetoresistance in all-altermagnetic tunnel junctions

In plain words

Theory predicts that a tunnel junction made only of altermagnets should change its resistance strongly when one electrode's spin pattern is reversed, giving a memory bit without ferromagnets. No experiment has yet shown this in a junction built only from altermagnets.

Precise statement

In an altermagnet/insulator/altermagnet junction (candidates CrSb, Cr-doped RuO2, KV2Se2O, MnTe) with no ferromagnetic layer, measure $\mathrm{TMR}=(R_{\mathrm{AP}}-R_{\mathrm{P}})/R_{\mathrm{P}}$ at $T=300\,\mathrm{K}$, where P and AP denote parallel and antiparallel Neel vectors, and determine whether it exceeds 100 percent as nonrelativistic spin-splitting theory predicts. An answer is the measured TMR with device structure and evidence that it arises from the altermagnetic band splitting.

What would settle it

Epitaxial all-altermagnet junctions with controlled Neel-vector switching and room-temperature TMR measurements.

Status in the literature

Unverified note

Work found for 2025-2026 is theoretical: a CrSb-based junction proposal (arXiv:2503.13850) and a first-principles all-altermagnet Cr-doped RuO2/TiO2/Cr-doped RuO2 junction (arXiv:2607.21092); no experimental all-altermagnet junction with TMR above 100 percent at 300 K was found.