Magnetic exchange interactions in room-temperature altermagnet KV2Se2O

Altermagnets unify the merits of ferromagnets (strong magneto responses) and antiferromagnets (zero stray fields), demonstrating time-reversal symmetry breaking, intrinsic demagnetization effects, and terahertz-range spin dynamics. These unique properties have attracted significant attention for spintronic applications requiring both robust spin control and minimal magnetic interference. Recently, KV2Se2O was identified as a metallic room-temperature altermagnetic material, but the origin of its high magnetic transition temperature remains elusive. In this work, it was found that both antiferromagnetic and ferromagnetic exchange coupling jointly play a crucial role in achieving the high magnetic transition temperature. Furthermore, K atoms enhance the magnetic moments of V atoms through charge transfer, thereby enhancing magnetic exchange energy and elevating the magnetic transition temperature. Additionally, strain effects can modulate the magnetic properties and the magnetic transition temperature, highlighting their potential for tailoring altermagnetism. These results not only motivate further exploration of room-temperature altermagnets but also pave the way for optimizing KV2Se2O in future magnetic and spintronic nanodevices.