Giant magnetoresistance and topological Hall effect in the EuGa4antiferromagnet

H Zhang; X Y Zhu; Y Xu; D J Gawryluk; W Xie; S L Ju; M Shi; T Shiroka; Q F Zhan; E Pomjakushina; T Shang

doi:10.1088/1361-648X/ac3102

Giant magnetoresistance and topological Hall effect in the EuGa₄antiferromagnet

J Phys Condens Matter. 2021 Nov 3;34(3). doi: 10.1088/1361-648X/ac3102.

Authors

H Zhang¹, X Y Zhu¹, Y Xu¹, D J Gawryluk², W Xie³, S L Ju⁴, M Shi⁴, T Shiroka^{5

6}, Q F Zhan¹, E Pomjakushina³, T Shang¹

Affiliations

¹ Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China.
² Laboratory for Multiscale Materials Experiments, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
³ DESY, Notkestraβe 85, D-22607 Hamburg, Germany.
⁴ Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
⁵ Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
⁶ Laboratorium für Festkörperphysik, ETH Zürich, CH-8093 Zurich, Switzerland.

PMID: 34666329
DOI: 10.1088/1361-648X/ac3102

Abstract

We report on systematic temperature- and magnetic field-dependent studies of the EuGa₄binary compound, which crystallizes in a centrosymmetric tetragonal BaAl₄-type structure with space groupI4/mmm. The electronic properties of EuGa₄single crystals, with an antiferromagnetic (AFM) transition atT_N∼ 16.4 K, were characterized via electrical resistivity and magnetization measurements. A giant nonsaturating magnetoresistance was observed at low temperatures, reaching∼7×104% at 2 K in a magnetic field of 9 T. In the AFM state, EuGa₄undergoes a series of metamagnetic transitions in an applied magnetic field, clearly manifested in its field-dependent electrical resistivity. BelowT_N, in the ∼4-7 T field range, we observe also a clear hump-like anomaly in the Hall resistivity which is part of the anomalous Hall resistivity. We attribute such a hump-like feature to the topological Hall effect, usually occurring in noncentrosymmetric materials known to host topological spin textures (as e.g., magnetic skyrmions). Therefore, the family of materials with a tetragonal BaAl₄-type structure, to which EuGa₄and EuAl₄belong, seems to comprise suitable candidates on which one can study the interplay among correlated-electron phenomena (such as charge-density wave or exotic magnetism) with topological spin textures and topologically nontrivial bands.

Keywords: magnetoresistance; topological Hall effect; topological spin textures.