Large Exchange Bias Effect in Geometrically Frustrated Spin Glass Through High-Density Coherent Chemical Interfaces

The pursuit of next-generation spintronic devices has focused heavily on compensated ferrimagnets and non-collinear antiferromagnets, thanks to their significant exchange bias (EB) effects and minimal stray fields. However, spin glass (SG) systems are reemerging as compelling candidates despite their historically weak EB responses and poorly understood pinning mechanisms. Herein, we report the discovery of a geometrically frustrated SG intermetal material (Mn₃₂Co₅In₁₅) exhibiting large EB effects (∼0.3 T), achieved by engineering high-density coherent interfaces. Specifically, this material features a 3D interlaced structure consisting of frustrated antiferromagnetic (f-AFM) Mn-rich clusters and ferromagnetic-like (FML) In-dominant clusters, consistent with topological spin glass states. Using field-dependent neutron scattering combined with theoretical calculations, we established the first experimental evidence that the large EB arises from the local pinning of FML states within frozen, coherent f-AFM matrices. This pinning breaks the ergodicity inherent to typical SG systems, while spin polarization of FML clusters creates an energetically favorable anisotropic channel in response to external fields. These findings offer new possibilities for leveraging frustrated spin glasses as pivotal functional materials in spintronic devices.