MSE Seminar Series: Dr. Jing Xia (UCI)

About this event

Flyer : Reading Magnets That Hide: Magneto-Optics of Compensated Magnets

Abstract : Compensated magnets, whose moments cancel, promise stray-field-free, dense and ultrafast spintronics, but magnetometers barely see them. Polarized light can. The Kerr effect reads the optical Hall conductivity, which is set by symmetry and band Berry curvature, not by magnetization. Using nanoradian Sagnac microscopes, we image this hidden response in three materials. Mn3NiN shows a temperature-invariant Kerr signal driven by spin–orbit coupling. Co1/3TaS2 shows a large Kerr signal from spin chirality alone, with strain-written nonvolatile states. In room-temperature altermagnetic MnTe, defects switch on a giant Kerr effect. I will close with the quantum metric, the less explored half of quantum geometry.