Magnetoresistance in Magnetic Weyl semimetal Mn${}_3$ZnC

Abstract

The magnetoresistance (MR) in magnetic materials reveal an intriguing spin-dependent electron scattering, highlighting the role of spin polarization on the electronic transport properties. This becomes even more interesting for the topological magnetic materials where a finite Berry curvature leads to an intrinsic scattering channel also. In this report, we investigate MR of Mn${}_3$ZnC, an antiperovskite magnetic nodal line semimetal. Mn${}_3$ZnC shows a ferromagnetic (FM) transition at $\sim$ 420 K, followed by an ferrimagnetic (FIM) transition at $\sim$ 195 K. We focus on the interpretation of MR data and highlight the relation between MR and its magnetization. The signature of magnetization induced MR shows correlation at low magnetic fields and displays distinct behaviors in the FIM and FM states. Similar to the isothermal magnetization M(H) curve of FM and FIM state, the MR curves exhibit a sharp increase, followed by a linear behavior at higher fields. As the magnetic field varies, the cusp-like anomaly becomes more pronounced, and vanishes at the magnetic phase transition, which then reappears as the temperature increases. The sign change in the MR curves in the FIM state is attributed to a drastic change in the carrier mobility. Interestingly, this system shows a positive MR in FM state at very low field, which is quite unusual.

7 pages, 4 figures