Coherent canted ferrimagnetism and higher-order anisotropy in the nodal-line magnetic semiconductor Mn3Si2Te6

TL;DR

This study uncovers the complex magnetic anisotropy in Mn3Si2Te6, revealing a canted ferrimagnetic ground state stabilized by multiple anisotropy terms, which explains its colossal angular magnetoresistance behavior.

Contribution

The paper combines magnetometry and spectroscopy to identify higher-order anisotropy terms that govern magnetization in Mn3Si2Te6, advancing understanding of magnetic topology in this material.

Findings

Identification of a coherent canted ferrimagnetic ground state.

Discovery of significant sixth-order anisotropy term (K3).

Reparameterization of CAMR in terms of magnetization angle.

Abstract

The interplay between magnetic order and electronic topology in van der Waals materials enables extreme responses to external stimuli. The nodal-line semiconductor Mn3Si2Te6 exemplifies this, exhibiting colossal angular magnetoresistance (CAMR) where resistivity changes by orders of magnitude upon rotating the magnetic field. While this phenomenon implies a profound coupling between spin orientation and charge transport, the microscopic magnetic potentials driving spin orientations remain elusive. Here, we combine thermodynamic torque magnetometry and electron spin resonance spectroscopy to reconstruct the magnetic anisotropy energy that controls magnetization rotation in Mn3Si2Te6. We show that low-temperature ground state is a coherent canted ferrimagnet stabilized by competing second- (K1) and fourth-order (K2) magnetic anisotropy. Crucially, torque requires a substantial symmetry-allowed sixth-order term (K3), which provides near-plane stiffness and sustains canting at high fields. Using the resulting anisotropy parameters, we compute the non-linear relation between field angle {\theta}_H and magnetization angle {\theta}_M and reparameterize CAMR in terms of {\theta}_M, providing a concrete magnetic basis for how sharp angular transport features can emerge near the in-plane configuration.