Tuning the chiral orbital currents in a colossal magnetoresistive nodal line ferrimagnet

TL;DR

This study investigates how chemical substitution of Te with Se in a ferrimagnetic nodal-line semiconductor affects chiral orbital currents and colossal magnetoresistance, revealing tunable magnetic and electronic properties.

Contribution

It demonstrates that substituting Te with Se weakens chiral orbital currents and modulates magnetoresistance, providing new insights into controlling CMR in nodal-line ferrimagnets.

Findings

Se substitution weakens chiral orbital currents

Magnetic field application reduces resistance along easy axis

Colossal magnetoresistance persists despite Se substitution

Abstract

The ferrimagnetic nodal-line semiconductor Mn$_3$Si$_2$Te$_6$ exhibits colossal magnetoresistance (CMR) owing to the chiral orbital currents (COC). The COC is developed due to spin-orbit interaction (SOI) attributed to the tellurium (Te) atoms. Here, we observe that on chemical substitution of the Te atoms with selenium (Se), the COC, which runs along the Te-Te edges of the MnTe$_6$ octahedra, becomes weaker and thus affects the angular magnetoresistance (MR) of Mn$_3$Si$_2$Te$_6$. We find that the application of magnetic field along the easy axis leads to a considerable drop in resistance in substituted crystals, which otherwise exhibits weak MR. On the other hand, the CMR effect along the partially polarized magnetization direction is found to be only marginally affected due to the substitution and persists even for a significantly high concentration of Se.