Piezomagnetic response of Altermagnets: preliminary report

 S.H. Sonny Rhim

Department of Physics, University of Ulsan, Ulsan 44610, South Korea

This talk is far from completion. Instead, it is preliminary progress report of

piezomagnetism of altermagnets.

For a long time, it has been believed that piezomagnetism only occur in ferromagnets not in antiferromagnets.

I revive old works by Dzyaloshinskii and Moriya in 50-60’s when they suggested possible piezomagnetism in RuO2, CoF2..

Later, Birss classified magnetic materials by so-called magnetic space group,

where some antiferromagnets fall into class, currently known as altermagnet.

Based on Birss’s classification, piezomagnetism is allowed for altermagnet.

At this moment, there is no elegant methodology of piezomagnetism, However, some trial, not necessarily perfect, is present,

to which any open discussion is welcome.

Ultrafast strain-induced spin dynamics

Jiwan Kim

Department of Physics, Kunsan National University, Kunsan 54150, South Korea

Magnetoelasticity, the spin – phonon interaction, is a ubiquitous phenomenon in magnetic materials and enables active control of spin dynamics through lattice deformations. When a material is excited by femtosecond laser pulses, two types of strains are generated: propagating pulses and quasi-static strain, both of which interact with spins. In this talk, I discuss their respective roles in governing spin dynamics. In addition, I address an often-overlooked issue arising from quasi-static strain, namely its impact on the validity and interpretation of magneto-optic measurements. Finally, I propose several experimental ideas involving altermagnetisms that could be explored on ultrafast time scales.