SKM 2021 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 3: Posters Magnetism I

MA 3.14: Poster

Montag, 27. September 2021, 13:30–16:30, P

Giant Topological Hall Effect in Noncollinear Phase of Two-dimensional Antiferromagnetic Topological Insulator MnBi4Te7 — •Subhajit Roychowdhury, Sukriti Singh, Satya N. Guin, Nitesh Kumar, Tirthankar Chakraborty, Walter Schnelle, Horst Borrmann, Chandra Shekhar, and Claudia Felser — Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany

Magnetic topological insulators provide an important platform for realizing several exotic quantum phenomena, such as the axion insulating state and quantum anomalous Hall effect, owing to the interplay between topology and magnetism. MnBi4Te7 is a two-dimensional Z_2 antiferromagnetic (AFM) topological insulator with a Néel temperature of ~13 K. In AFM materials, the topological Hall effect (THE) is observed owing to the existence of nontrivial spin structures. In this study, we observed that an unanticipated THE starts to develop in a MnBi4Te7 single crystal when the magnetic field is rotated away from the easy axis (c-axis) of the system. Furthermore, the THE resistivity reaches a giant value of ~7 microΩcm at 2 K when the angle between the magnetic field and c-axis is of 75°. This value is significantly higher than the values for previously reported systems with noncoplanar structures. The THE can be ascribed to the noncoplanar spin structure resulting from the canted state during the spin-flop transition in the ground AFM state of MnBi4Te7. The large THE at a relatively low applied field makes the MnBi4Te7 system a potential candidate for spintronic applications.