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Spin chirality induced large topological Hall effect in magnetic Weyl semimetallic Eu2 Ir2 O7 (111) thin films

Ghosh, M and Samal, D and Anil Kumar, PS (2022) Spin chirality induced large topological Hall effect in magnetic Weyl semimetallic Eu2 Ir2 O7 (111) thin films. In: Physical Review B, 106 (8).

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Official URL: https://doi.org/10.1103/PhysRevB.106.085139


Antiferromagnetic (AFM) pyrochlore iridates are a fertile ground to hunt for a Weyl semimetallic state characterized by a linear crossing of two nondegenerate bands near the Fermi level EF. Here, we demonstrate evidence of low-temperature anomalous and topological Hall effects in an antiferromagnetic Eu2Ir2O7(111) epitaxial thin film. The observed anomalous Hall effect is explained in terms of the momentum space Berry curvature associated with the Weyl nodes in the electronic band structure. The topological Hall effect reaches a large value ρxyTHE∼10μωcm at 2 K. The topological nature of the Hall effect is attributed to the nonzero scalar spin chirality of the all-in-all-out/all-out-all-in (AIAO/AOAI) type noncoplanar AFM spin structure. The magnetoresistance (MR) shows a prominent negative variation (MR∼10% at 2 K) below 10 K. The field dependence of MR below 5 K varies quadratically in the low-field regime, and above 40 kOe it shows a linear trend. The quadratic to linear crossover of the MR is explained by the field-induced (H) spin canting (spin chirality) of the static spins in the AIAO/AOAI spin structure. In the intermediate-temperature region MR of 15-25 K exhibits a hysteretic response which is associated with field-induced domain switching of the AIAO/AOAI spin structure. This work highlights the interplay of magnetism and topology in a spin-orbit-coupled correlated electron system and unravels the possibility for realizing the Weyl phase in antiferromagnetic Eu2Ir2O7(111) thin films.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: The copyright for this article belongs to the American Physical Society.
Keywords: Antiferromagnetism; Chirality; Spin Hall effect; Thin films; Topology, Antiferromagnetics; Epitaxial thin films; Field-induced; Lows-temperatures; Nondegenerate; Pyrochlores; Semimetallics; Spin chirality; Spin structures; Thin-films, Temperature
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 06 Oct 2022 11:21
Last Modified: 06 Oct 2022 11:21
URI: https://eprints.iisc.ac.in/id/eprint/77231

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