Spin fluctuation under electric current in Colossal Magnetoresistance in Mn₃Si₂Te₆

The colossal magnetoresistance (CMR) observed in Mn₃Si₂Te₆ represents a striking deviation from conventional CMR materials [1-3]. This compound exhibits an insulator–metal transition, characterized by an orders-of-magnitude drop in resistivity when a magnetic field exceeding 4 T is applied along the magnetic hard c axis —an effect absent when the field is applied within the basal plane. Single-crystal neutron diffraction measurement revealed pronounced short-range magnetic diffuse scattering near the magnetic transition, indicative of strong spin fluctuation. The close correlation between the spin correlation lengths and electrical resistivity highlights the critical role of fluctuating spins in governing the transport properties. Applying an in-plane electric current suppresses the diffuse scattering and induces a first-order like structural transition, thereby modifying the low-temperature magnetic ground state. These observations point to a fundamentally different mechanism underlying the magnetotransport behavior in Mn₃Si₂Te₆, distinct from conventional spin-polarization-driven model.

[1]        Y. Ni et al., Phys. Rev. B 103, L161105 (2021).

[2]        J. Seo et al., Nature 599, 576 (2021).

[3]        Y. Zhang et al., Nature 611, 467 (2022).

[4]        F. Ye et al., Phys. Rev. B 106, L108402 (2022).