Currently, magnetic memory devices use the ↑ and ↓ spin states of ferromagnetic materials to store information. In the 2020s, the novel concept of ‘altermagnet’ has theoretically been proposed, which stores information in the ↑↓ and ↓↑ spin states and enables their reading and writing by similar approaches as ferromagnetic materials.
In this study, a research group led by Prof. Shinichiro Seki has successfully discovered the first example of room-temperature altermagnet with non-volatile memory function. They experimentally demonstrated that a magnetic semiconductor FeS (iron sulfide) is a room-temperature altermagnet, where information can be stored by the ↑↓ and ↓↑ spin states in the absence of external fields and these two states can be read out electrically.
Unlike ferromagnetic materials that have been used in the past, altermagnetic materials have advantageous features for application, such as (1) suitability for device integration due to the absence of stray field causing interference between neighboring bits, (2) 100 times faster response speed, and (3) robustness against magnetic disturbance. The present discovery of room-temperature altermagnetic material with non-volatile memory function will lead to its potential application as next-generation information media with ultra-high density, ultra-high speed and ultra-low energy consumption.
Papers
Journal: Nature Materials
Title: Spontaneous Hall effect induced by collinear antiferromagnetic order at room temperature
Authors: R. Takagi*, R. Hirakida, Y. Settai, R. Oiwa, H. Takagi, A. Kitaori, K. Yamauchi, H. Inoue, J. Yamaura, D. Nishio-Hamane, S. Itoh, S. Aji, H. Saito, T. Nakajima, T. Nomoto, R. Arita, S. Seki*