Uncovering magnetic structures underneath giant spontaneous exchange bias effect in a kagome magnet

The exchange bias (EB) effect,characterized by a shift of the hysteresis loop,plays a key role in spintronics and magnetic recording. The mechanism of EB effect is still lacking, what we know isthat EB effect originates from the pinned uncompensated magnetic moments. Recently, reports show EB effect is observed in single-phase materials which origin from multiple magneticbehaviors, e.g. AFM/FM, spin glass/FM, and spin glass/AFM. And These single-phase materials are also more appropriate as prototypes to understand the mechanism of EB effect usingtechniques which are difficult to apply on heterostructures like neutron diffraction. The hexagram-like kagome lattice, a “functional group” with giant geometrical frustration, exhibits diversemagnetic behaviors. Utilizing kagome lattice, we design a giant spontaneous EB effect in TbMn6(Ge, Ga)6 as large as 1.25 T at 5 K.