Large anisotropic magnetoresistance in paramagnetic Fe-doped Ta4SiTe4
Abstract
Large anisotropic magnetoresistance (AMR) usually relies on magnetic ordering, which fixes a preferred moment orientation and couples it to charge transport. Here, we demonstrate that pronounced AMR can instead arise from the anisotropic magnetic-field-induced polarization of dilute local moments in paramagnetic Fe-doped Ta4SiTe4, a quasi-one-dimensional van der Waals narrow-gap semiconductor. Magnetization measurements reveal Curie-like paramagnetism down to 2 K, with the c axis as the magnetic easy axis. The magnetization is described by an effective S = 1/2 model with an anisotropic g-factor ratio of g_c/g_ab = 1.43(1). With the electrical current applied along the c axis, the Fe-doped sample exhibits a large negative magnetoresistance for B//c and only a weak positive response for B//ab, whereas the undoped sample shows little magnetoresistance for either field orientation. The resulting AMR ratio reaches -33% at 8 K and 10 T and exhibits a nonmonotonic temperature dependence qualitatively captured by a minimal spin-disorder model. These results show that engineering the local environment of dilute magnetic ions provides a route to large paramagnetic AMR without long-range magnetic order, extending the materials design space for AMR beyond magnetically ordered systems.
Related
- Anisotropic magnetoresistance of two-dimensional Rashba systems with in-plane Zeeman field and point-like disorder
- Electron paramagnetic resonance of Dy3+-doped CaWO4: spin Hamiltonian, crystal-field analysis, and linear electric field effect
- Electronic structure, magnetic order and anisotropic magnetoresistance in Eu1−xGdxCd2P2 (0 ≤ x ≤1)
- Antiphase boundary-driven large exchange bias and negative magnetoresistance in NiCo2O4
- Orbital magnetoresistance in the antiferromagnet CoO driven by dynamic orbital angular momentum
BibTeX
@misc{nagasawa2026large,
title = {{Large anisotropic magnetoresistance in paramagnetic Fe-doped Ta4SiTe4}},
author = {Keita Nagasawa and Ryutaro Okuma and Jun-ichi Yamaura and Yoshihiko Okamoto},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.29463},
eprint = {2610.29463},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.29463},
}
RIS
TY - UNPB
TI - Large anisotropic magnetoresistance in paramagnetic Fe-doped Ta4SiTe4
AU - Keita Nagasawa
AU - Ryutaro Okuma
AU - Jun-ichi Yamaura
AU - Yoshihiko Okamoto
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.29463
UR - https://arxiv.org/abs/2610.29463
AB - Large anisotropic magnetoresistance (AMR) usually relies on magnetic ordering, which fixes a preferred moment orientation and couples it to charge transport. Here, we demonstrate that pronounced AMR can instead arise from the anisotropic magnetic-field-induced polarization of dilute local moments in paramagnetic Fe-doped Ta4SiTe4, a quasi-one-dimensional van der Waals narrow-gap semiconductor. Magnetization measurements reveal Curie-like paramagnetism down to 2 K, with the c axis as the magnetic easy axis. The magnetization is described by an effective S = 1/2 model with an anisotropic g-factor ratio of g_c/g_ab = 1.43(1). With the electrical current applied along the c axis, the Fe-doped sample exhibits a large negative magnetoresistance for B//c and only a weak positive response for B//ab, whereas the undoped sample shows little magnetoresistance for either field orientation. The resulting AMR ratio reaches -33% at 8 K and 10 T and exhibits a nonmonotonic temperature dependence qualitatively captured by a minimal spin-disorder model. These results show that engineering the local environment of dilute magnetic ions provides a route to large paramagnetic AMR without long-range magnetic order, extending the materials design space for AMR beyond magnetically ordered systems.
ER -