Topological Hall Effect in Traditional Ferromagnet Embedded with Black-Phosphorus-Like Bismuth Nanosheets

Abstract

We implement the molecular beam epitaxy method to embed the black-phosphorus-like bismuth nanosheets into the bulk ferromagnet Cr2Te3. As a typical surfactant, bismuth lowers the surface tensions and mediates the layer-by-layer growth of Cr2Te3. Meanwhile, the bismuth atoms precipitate into black-phosphorus-like nanosheets with the lateral size of several tens of nanometers. In Cr2Te3 embedded with Bi-nanosheets, we observe simultaneously a large topological Hall effect together with the magnetic susceptibility plateau and magnetoresistivity anomaly. As a control experiment, none of these signals is observed in the pristine Cr2Te3 samples. Therefore, the Bi-nanosheets serve as seeds of topological Hall effect induced by non-coplanar magnetic textures planted into Cr2Te3. Our experiments demonstrate a new method to generates a large topological Hall effect by planting strong spin-orbit couplings into the traditional ferromagnet, which may have potential applications in spintronics.

Near Degeneracy of Magnetic Phases in Two-Dimensional Chromium Telluride with Enhanced Perpendicular Magnetic Anisotropy

“…The field dependence arising from this weak energy variation may qualitatively explain the zero-field kink observed in the magnetic hysteresis loops. In this context, it is worth mentioning that a large topological Hall effect has recently been reported in Cr 2 Te 3 embedded with Bi atoms or coupled with Bi 2 Te 3 , indicating the existence of magnetic skyrmions, a topologically nontrivial vortex spin configuration. The “continuous” spin-canting in the thin layers of undoped Cr 2 Te 3 observed in this work may provide insight into the nature of these skyrmions, which offer opportunities for ultracompact information storage and processing applications based on spintronic devices.…”

Emergence of Nontrivial Spin Textures in Frustrated Van Der Waals Ferromagnets

“…The topological Hall effect (THE) is the abnormal Hall response from the scalar spin chirality of magnetic textures [ 92 ]. In the MS state, the skyrmion THE is an equivalent Hall response due to an emergent magnetic field, which is an effect attributable to the Berry skyrmion phase [ 93 ].…”

Berry Phase Engineering in SrRuO3/SrIrO3/SrTiO3 Superlattices Induced by Band Structure Reconstruction

“…[1][2][3][4][5] THE is currently employed as a promising tool to explore the Dzyaloshinskii-Moriya interaction (DMI) and the formation of magnetic 3 skyrmions. [6][7][8][9][10] However, in addition to the chiral magnetic structure in real space, other mechanisms such as Berry phase engineering, which is related to band structure reconstruction in the momentum space, also account for this observed hump-like feature in the Hall resistivity loop. [11][12][13] This phenomenon is especially prominent in systems with a ferromagnetic order and strong spin-orbit coupling (SOC) because the Berry phase, which acts as a source of an emergent magnetic field, is strongly enhanced in the vicinity of the band anti-crossings.…”

“…The topological Hall effect (THE) manifests as a hump-like feature in the curves of the anomalous Hall effect (AHE) as a function of the applied magnetic field. THE has been ascribed to the Berry phase acquired by spin-polarized carriers passing through a chiral magnetic structure. − The THE is currently employed as a promising tool to explore the Dzyaloshinskii–Moriya interaction (DMI) and the formation of magnetic skyrmions. − However, in addition to the chiral magnetic structure in real space, other mechanisms such as Berry phase engineering, which is related to band structure reconstruction in the momentum space, also account for this observed hump-like feature in the Hall resistivity loop. − This phenomenon is especially prominent in systems with a ferromagnetic order and strong spin–orbit coupling (SOC) because the Berry phase, which acts as a source of an emergent magnetic field, is strongly enhanced in the vicinity of the band anti-crossings . This work aims to develop a deeper understanding of the physics underlying this hump-like feature.…”