Anisotropic Anomalous Hall Effect Research Articles

Large topological Hall effect near room temperature in noncollinear ferromagnet LaMn2Ge2 single crystal

Non-trivial spin structures in itinerant magnets can give rise to topological Hall effect (THE) due to the interacting local magnetic moments and conductive electrons. While, in series of materials, THE has mostly been observed at low temperatures far below room temperature (RT) limiting its potential applications. Here, we report the anisotropic anomalous Hall effect (AHE) near RT in LaMn2Ge2, a noncollinear ferromagnetic (FM) with Curie temperature TC=325 K. Large topological Hall resistivity of ~1.0 10-6 ohmcm in broad temperature range (190 K <T< 300 K) is realized as field (H) parallel to the ab-plane (H // ab) and current along c axis (I // c), in contrast to the conventional AHE for H // c and I // ab. The emergence of THE is attributed to the spin chirality of noncoplanar spin configurations stabilized by thermal fluctuation during spin flop process. Moreover, the constructed temperature-field (H-T) phase diagrams based on the isothermal topological Hall resistivity reveal a field-induced transition from the noncoplanar spin configuration to polarized ferromagnetic states. Our experimental realization of large THE near RT highlights LaMn2Ge2 as a promising system for functional applications in novel spintronic devices.

Magnetic anisotropy and topological Hall effect in the trigonal chromium tellurides Cr5Te8

Nontrivial spin configurations tend to bring about novel transport properties in magnetic materials. We report the magnetic anisotropy and topological Hall effect in trigonal ${\mathrm{Cr}}_{5}{\mathrm{Te}}_{8}$ single crystals. Below the magnetic transition temperature, the spins are canted ferromagnetic aligned along $c$ axis with antiferromagnetic components in $ab$ plane. This peculiar magnetic structure gives rise to the anisotropic anomalous Hall effect (AHE) in ${\mathrm{Cr}}_{5}{\mathrm{Te}}_{8}$. When the current flows along the $ab$ plane, ${\mathrm{Cr}}_{5}{\mathrm{Te}}_{8}$ exhibits a conventional AHE depicted by skew scattering mechanism. On the other hand, the topological Hall effect appears with current along $c$ axis, which stems from the noncoplanar spin configuration with scalar spin chirality during the spin flop process.

Anisotropic Anomalous Hall Effect of Topological Origin in Carrier-Doped FeCr2S4

The anomalous Hall effect (AHE) was investigated for a single crystal of 6% Ag-doped FeCr 2 S 4 with the rotation of the magnetic field ( H ) within the y z plane (the current along \(\hat{x}\), the Hall voltage along \(\hat{y}\)). We observed a clear deviation from the cos θ dependence (θ being the angle between H and \(\hat{z}\)), which indicates the presence of an anisotropic AHE. We analyzed a tight-binding model of the diamond lattice with the Dzyaloshinskii–Moriya interaction and reproduced the characteristic experimentally observed features. The quantum topology nature of the AHE is revealed in this compound.