Emergent Multiple Spin States From Baromagnetic Effect in Strongly Correlated Magnet Mn₃GaC

Strongly correlated magnets, exhibiting distinctive spin properties such as spin-orbit coupling, spin polarization, and chiral spin, are regarded as the next-generation high-density magnetic storage materials in spintronics. Nevertheless, owing to intricate spin interactions, realizing controllable spin arrangement and high-density magnetic storage remains a formidable challenge. Here, controllable multiple spin states induced by the baromagnetic effect in kagome lattice magnet Mn₃GaC are first reported, achieved by manipulating spin rotation within the spin-polarized plane employing pressure. Neutron diffraction refinement and specific heat measurements under pressure, combined with first-principles calculations, demonstrate that multiple spin states are originating from the synergistic mechanism between spin frustration and spin polarization related to the lifting of degeneracy in electronic microstates. Electrical transport measurements under pressure reveal that multiple spin states exhibit giant baro-magnetoresistance effect, enabling enhanced storage density in spintronics via multi-logic state applications. Integrating the pressure response and microscopic behaviors of spins, a comprehensive p-T-H phase diagram is constructed, offering a novel and robust framework for multi-logic states. These findings provide critical insights into controllable spin states, opening a new avenue for high-density magnetic storage through multiple spin states.