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We have observed robust chiral spin torques and non-reciprocal charge transport behaviors in the α-Fe2O3/Pt bilayers through a combination of magnetic field and current-dependent second longitudinal harmonic resistance measurements. The interfacial Dzyaloshinskii–Moriya interaction induced magnetic chirality has been predicted to account for the sign reversal characteristic of the second longitudinal harmonic resistance with increasing the current amplitude. A physical model that considers the chirality dependence of both the asymmetric scattering and the giant Rashba spin–orbit coupling has been set up to uncover the microscopic interactions between charge, spin, and magnetic chirality. Our comprehensive approach leverages the semiclassical Boltzmann theory to validate the consistency between this model and our experimental findings. Through our investigation, we have established the pivotal role of interfacial magnetic chirality in determining both charge and spin transport behaviors within antiferromagnetic insulator/heavy metal bilayer systems. Our work not only enhances the comprehension of spin–orbit torques and non-reciprocal charge transport but also contributes to the broader understanding of these phenomena. The outcomes of this study have broader implications for the advancement of spintronics and related fields. [ABSTRACT FROM AUTHOR]

Thin films of Bi1.05La0.05FeO3 (BLFO) have been deposited on a CaRuO3 buffering layer on SrTiO3 using pulsed laser deposition. Then, a Pt thin layer was in situ sputtered on the surface of BLFO. The crystallization characteristic and surface morphology of the BLFO layer were checked. Spin transporting behaviors of the Pt/BLFO structure were investigated at room temperature. Interestingly, a magnetoresistance effect was observed at the interface of the Pt/BLFO bilayer. The spin mixing conductance at the interface between BLFO and Pt was estimated after a corrections of Pt thickness. This implies that the manipulation of spin–orbit coupling is possible at the interface of a single-phase multiferroic (e.g., BLFO) and a heavy metal (e.g., Pt). [ABSTRACT FROM AUTHOR]

Nonreciprocal charge transport, which is frequently termed as electrical magnetochiral anisotropy (EMCA) in chiral conductors, touches the most important elements of modern condensed matter physics. Here, we have investigated the large EMCA in Pt/PtMnGa (PMG) bilayers, which can be attributed to the nonreciprocal response of an interface-driven chiral transport channel. Different from the traditional linear current-dependent EMCA, for Pt/PMG bilayers, higher-order EMCA coefficients should be phenomenally added especially for the small current region. This unusual behavior has been explained based on both quantum transport and semiclassical transport models. Furthermore, a combination of asymmetrical electron scattering and spin-dependent scattering furnish the PMG thickness-dependent chiral transport behaviors in Pt/PMG bilayers. The dramatically enhanced anomalous Hall angle of PMG further demonstrates the modified surface state properties by strong spin–orbit coupling. [ABSTRACT FROM AUTHOR]

The spin currents generated by spin–orbit coupling in nonmagnetic metals or at interfaces with broken inversion symmetry are particularly important for devices with extraordinary performance. We have investigated the spin–orbit torques (SOTs) in Ru/Fe/HfO2 heterostructures with weak perpendicular magnetic anisotropy. Although the bulk spin Hall effect (SHE) of the Ru layer is smaller than that of Pt, Ta, or W, robust SOT-induced magnetization switching can also be realized. Through nonadiabatic harmonic measurements, the effective spin Hall angle in Ru/Fe/HfO2 heterostructures is calculated to be −0.045. We have explored the mechanisms of spin current generation, which could stem from the Ru/Fe interfaces other than the weak bulk SHE of Ru. Our results suggest the spin current generation mechanisms in ferromagnet/nonmagnetic metal heterostructures remain to be further explored. [ABSTRACT FROM AUTHOR]

We report the enhancement of spin-orbit torques (SOT) in MnAl/Ta films with improving chemical ordering through annealing. The switching current density is increased due to enhanced saturation magnetization MS and effective anisotropy field HK after annealing. Using harmonic measurements, we have found that both dampling-like effective field HD and field-like effective field HF were increased in the temperature range of 50 to 300 K, and the annealing has also enhanced the value of the spin Hall angle. The improved chemical ordering is considered to have enhanced the interfacial spin transparency and the transmitting of the spin current in the MnAl layer. The results suggest that MnAl films with high bulk perpendicular magnetic anisotropy are ideal for a systematic examination of SOT, in which the related magnetic and transport behaviors can be controllably varied with thermally tuned chemical ordering. [ABSTRACT FROM AUTHOR]

We report systematic measurements of anomalous Hall effect (AHE) in Mn1.5Ga/Ta and Mn1.5Ga/Pt bilayers modified by strong spin-orbit coupling (SOC) of the heavy metals. The results are compared with the AHE in Mn1.5Ga/Cu with weak SOC. We have used a scaling involving multiple competing scattering mechanisms to distinguish different contributions to the modified AHE. The scaling analysis reveals that the origin of the modified AHE in Mn1.5Ga/Cu is different from those in Mn1.5Ga/Ta and Mn1.5Ga/Pt. The direct observation of spin-orbit torque induced magnetization switching confirms that the result is a combination of the AHE of Mn1.5Ga and spin Hall effect of the heavy metals. [ABSTRACT FROM AUTHOR]