Current and Voltage relationship in Chiral Orbital Current Material Mn₃Si₂Te₆

Colossal Magnetoresistance (CMR) is characterized by a dramatic drop in resistivity under small magnetic field. A similar effect, Magnetoresistance, has been utilized in magnetic memory storage to significant effect. CMR has great potential to be applied in similar systems. CMR generally occurs when the applied magnetic field induces strong spin polarization, limiting spin scattering and resistance. Ferrimagnetic Mn₃Si₂Te₆ displays CMR when the magnetic field is applied to the magnetic hard c axis. Thus, this CMR effect is not associated with magnetic ordering. This can instead be explained by a chiral orbital current (COC) encircling the MnTe octahedra. The orbital moments of the COC couple with the Mn spins to exhibit the CMR effect when a magnetic field is applied to the c-axis. These properties can induce time-dependent bistable switching when a small current is induced along the ab plane, similar to the “melting transitions” common in CMR materials. While the I-V relationship of Mn₃Si₂Te₆ has been demonstrated in previous publications, variations of this material with different doping have not been explored. When the Si site is doped by 8% with Ge atoms, the unit cell volume is increased, and all effects of the COC are increased, including a larger CMR drop and lower overall magnetization. Conversely, when the Te site is doped with Se, the opposite effect is observed. The unit cell volume is decreased, the order of magnitude of the CMR is reduced, and the overall magnification is increased. By exploring the I-V relationships in these Mn₃Si₂Te₆ derivatives, we hope to develop a better understanding of COC materials.