Altermagnets exhibit characteristics akin to antiferromagnets, with spin-split anisotropic bands in momentum space. RuO2 has been considered as a prototype altermagnet; however, recent reports have questioned altermagnetic ground state in this material. In this study, we provide direct experimental evidence of altermagnetic characteristics in RuO2 films by demonstrating spin-dependent tunneling magnetoresistance (TMR) in RuO2-based magnetic tunnel junctions. Our results show the spin-splitted anisotropic band structure of RuO2, with the observed TMR determined by the direction of the N\'eel vector of RuO2. These results reflect the altermagnetic nature of RuO2 and highlight its potential for spintronic applications, leveraging the combined strengths of ferromagnetic and antiferromagnetic systems.
@article{arxiv.2502.13599,
title = {Tunneling magnetoresistance in altermagnetic RuO$_2$-based magnetic tunnel junctions},
author = {Seunghyeon Noh and Gye-Hyeon Kim and Jiyeon Lee and Hyeonjung Jung and Uihyeon Seo and Gimok So and Jaebyeong Lee and Seunghyun Lee and Miju Park and Seungmin Yang and Yoon Seok Oh and Hosub Jin and Changhee Sohn and Jung-Woo Yoo},
journal= {arXiv preprint arXiv:2502.13599},
year = {2025}
}