Ultrafast phononic switching of magnetization

Identifying efficient pathways to control and modify the order parameter of a macroscopic phase in materials is an important ongoing challenge. One way to do this is via the excitation of a high-frequency mode that couples to the order, and this is the ultimate goal of the field of ultrafast phase transitions(1,2). This is an especially interesting research direction in magnetism, where the coupling between spin and lattice excitations is required for magnetization reversal(3,4). However, previous attempts(5,6) have not demonstrated switching between magnetic states via resonant pumping of phonon modes. Here we show how an ultrafast resonant excitation of the longitudinal optical phonon modes in magnetic garnet films switches magnetization into a peculiar quadrupolar magnetic domain pattern, revealing the magneto-elastic mechanism of the switching. In contrast, the excitation of strongly absorbing transverse phonon modes results in a thermal demagnetization effect only.

Automated summary

Researchers have achieved switching of magnetization in magnetic garnet films by ultrafast resonant excitation of longitudinal optical phonon modes, revealing the magneto-elastic mechanism of the switching. In contrast, excitation of strongly absorbing transverse phonon modes results in a thermal demagnetization effect only.