Search

Abstract Accurately predicting the spin Hall conductivity (SHC) is crucial for designing novel spintronic devices that leverage the spin Hall effect. First‐principles calculations of SHCs are computationally intensive and unsuitable for quick high‐throughput screening. Here, we have developed a residual crystal graph convolutional neural network (Res‐CGCNN) deep learning model to classify and predict SHCs solely based on the structural and compositional information. This is enabled by having access to 9249 instances of SHCs data and incorporating extra residual networks into the standard CGCNN framework. We found that Res‐CGCNN surpasses CGCNN, achieving a mean absolute error of 115.4 (ℏ/e) (S/cm) for regression and an area under the receiver operating characteristic curve of 0.86 for classification. Additionally, we utilized Res‐CGCNN to conduct high‐throughput screenings of materials in the Materials Project database that were absent in the training set. This led to the prediction of several previously unreported materials displaying large SHCs exceeding 1000 (ℏ/e) (S/cm), which were validated through first‐principles calculations. This study represents the inaugural endeavor to construct a machine learning model capable of effectively capturing the intricate nonlinear relationship between SHCs and crystal structure and composition, serving as a useful tool for the efficient screening and design of materials exhibiting high SHCs.

Featured Application: Our theoretical studies report the anomalous and spin Hall conductivities of Co3−xCrxAl Heusler compounds in the L21 crystal structure. Based on density functional theory, we studied the electronic, magnetic, and mechanical properties of Co3−xCrxAl (x = 0, 1, 2, 3) Heusler compounds with the generalized gradient approximation (GGA) for the exchange-correlation potential. In this study, we report two principal spin-related phenomena, namely, the anomalous Hall effect and current spin polarization of the Co3−xCrxAl Heusler compounds in the L21 crystal structure. Heusler compounds, both ideally and inversely ordered, were considered. We found that the calculated magnetic moment of Co3−xCrxAl decreased with an increase in the Cr concentration for both ideally and inversely ordered structures, except for Cr3Al. We also found that the spin polarization for all Co3−xCrxAl was larger than 50%, except for Cr2CoAl in the inverse structure. All the considered Heusler compounds were mechanically stable except for the regular Cr2CoAl. The Hall current spin polarization was also calculated. We found that Co2CrAl in the XA structure had the largest spin Hall conductivity of 370 ( ℏ S / e   cm ), and the spin polarization of the induced Hall current was high. [ABSTRACT FROM AUTHOR]

[Display omitted] • First-principle calculation predicts spin Hall conductivity of −1461(ℏ/e)S/cm at Ti 12.5 a%. • A magnetic heterojunction with β-W-Ti 11.5 a% shows a spin-orbit torque efficiency of 0.54. • Spin-orbit torque switching maintains for temperatures ranging from −55 °C to 150 °C. Spin-orbit torque (SOT) switching has gained significant interest, particularly in the context of non-volatile embedded memory for advanced automotive vehicles. The study of temperature-dependent SOT switching, a less explored area, is crucial for developing automotive electronics Grade-0, which requires an ambient operating temperature range from −40 to 150 °C. These SOT devices demand substantial SOT efficiency to ensure a low operating current. Additionally, materials employed in these devices must be compatible with semiconductor fabrication. This study presents the first principles calculations to estimate the spin Hall conductivity (σ SH) change of Ti-alloyed β-phase W structures depending on the Ti composition. The calculation predicts the highest σ SH value of −1461 (ℏ/e) S/cm at Ti 12.5 at%. In addition, we fabricate β-W-Ti (x at%) 5/Co 40 Fe 40 B 20 0.9/MgO 1 (in nm) heterojunctions with various Ti compositions to confirm the above result experimentally. Under the controllable experimental condition, we observe the heterojunction with β-W-Ti 11.5 at% exhibits an enhanced damping-like SOT efficiency of 0.54 (compared to 0.30 of pure β-W) with longitudinal resistivity of 149.7 μΩ·cm. The critical current density (J c) reaches as low as 15.5 cm2. We also demonstrate that SOT switching is possible at ambient temperatures ranging from −55 to +150 °C. [ABSTRACT FROM AUTHOR]

A comprehensive exploration of the intriguing phenomena known as the spin Nernst effect (SNE) and the spin Hall effect (SHE) within the context of nonmagnetic strong topological insulatorZnCu2SnSe4, has been carried out employing first-principles calculations. Our theoretical calculations unveil significantly large intrinsic spin Nernst conductivity (SNC) and spin Hall conductivity (SHC) in the bulk topological insulatorZnCu2SnSe4. Delving deeper into the intricacies of our findings, we elucidate how the inverted band order in the topological materials drastically influences the spin Berry curvature, consequently exerting a profound impact on SHC and SNC. Detailed analyses reveal that the contribution from the bulk to the generation of pure spin current in a topological insulator is comparable to that of a surface. This underscores the potential role of topological insulators in the development of spin-switching devices. We present compelling evidence thatZnCu2SnSe4holds immense promise as an optimal candidate for the generation of pure spin currents, achieved through the application of both thermal gradients and electric fields. This, in turn, opens up exciting avenues for its utilization in the realms of spin-caloritronics, spin-orbitronics, and spintronics., (© 2024 IOP Publishing Ltd.)

Complex oxides with 4d/5d transition metal ions, e.g., SrRuO3, usually possess strong spin–orbit coupling, which potentially leads to efficient charge‐spin interconversion. As the electrical transport property of SrRuO3 can be readily tuned via structure control, it serves as a platform for studying the manipulation of charge‐spin interconversion. Here, a factor of twenty enhancement of spin–orbit torque (SOT) efficiency via strain engineering in a SrRuO3/Ni81Fe19 bilayer is reported. The results show that an orthorhombic SrRuO3 leads to a higher SOT efficiency than the tetragonal one. By changing the strain from compressive to tensile in the orthorhombic SrRuO3, the SOT efficiency can be increased from an average value of 0.04 to 0.89, corresponding to a change of spin Hall conductivity from 27 to 441 × ħ/e (S cm−1). The first‐principles calculations show that the intrinsic Berry curvature can give rise to a large spin Hall conductivity (SHC) via the strain control, which is consistent with the experimental observations. The results provide a route to further enhance the SOT efficiency in complex oxide‐based heterostructures, which will potentially promote the application of complex oxides in energy‐efficient spintronic devices. [ABSTRACT FROM AUTHOR]

Based on density functional theory, we studied the electronic, magnetic, and mechanical properties of Co3−xCrxAl (x = 0, 1, 2, 3) Heusler compounds with the generalized gradient approximation (GGA) for the exchange-correlation potential. In this study, we report two principal spin-related phenomena, namely, the anomalous Hall effect and current spin polarization of the Co3−xCrxAl Heusler compounds in the L21 crystal structure. Heusler compounds, both ideally and inversely ordered, were considered. We found that the calculated magnetic moment of Co3−xCrxAl decreased with an increase in the Cr concentration for both ideally and inversely ordered structures, except for Cr3Al. We also found that the spin polarization for all Co3−xCrxAl was larger than 50%, except for Cr2CoAl in the inverse structure. All the considered Heusler compounds were mechanically stable except for the regular Cr2CoAl. The Hall current spin polarization was also calculated. We found that Co2CrAl in the XA structure had the largest spin Hall conductivity of 370 (ℏS/e cm), and the spin polarization of the induced Hall current was high.

Controlling charge‐spin current conversion by electric fields is crucial in spintronic devices, which can now be realized in diatom ferroelectric semiconductor GeTe. It is well demonstrated that ferroelectricity can change the spin texture in this compound. Herein, it is shown that the spin Hall conductivity (SHC) can be further tuned by ferroelectricity based on the density functional theory calculations. The spin texture variation driven by the electric fields is elucidated from the symmetry point of view, highlighting the interlocked spin and orbital degrees of freedom. It is observed that the origin of SHC can be attributed to the Rashba effect and the intrinsic spin–orbit coupling. The magnitude of one component of SHC σxyz can reach as large as 100 ℏ/e (Ω−1 cm−1) in the vicinity of the band edge, which is promising for engineering spintronic devices. The work on tunable spin transport properties via the ferroelectric polarization brings novel assets into the field of spintronics. [ABSTRACT FROM AUTHOR]

The conductive monolayer 1 T TaS 2 is a promising candidate to promote spintronic devices to the next level. Through first-principle calculations, we demonstrate that the intrinsic spin Hall conductivity (ISHC) in conductive monolayer 1 T TaS 2 and its interfaces with graphene can be engineered by strain through manipulating the orbital texture of the material. First, we quantitatively study orbital hybridization in monolayer TaS 2 under compressive and tensile strains. Next, by calculating the spin Berry curvature (SBC) of the bands over the whole BZ, we investigate the spin Hall conductivity of the pristine and strained monolayer TaS 2. With a detailed analysis of the band structure and characterizing the change in the concavity of the bands in the vicinity of the Fermi level, we identify the responsible features for the tunable ISHC to be hybridization strength in conjugation with spin–orbit coupling (SOC). Furthermore, our SBC projected band structure calculations point toward an interesting correlation between the magnitude of the ISHC and the p d hybridization strength. Inspired by the correlation between orbital hybridization and ISHC values, we next look at the heterostructure of graphene and monolayer TaS 2. Our calculations show that upon orbital mixing between the two materials, a large ISHC of 235 ħ e Ω − 1 cm−1 can be realized which is comparable to many pioneering materials with spintronic applications. These findings suggest possible routes to design novel materials for spintronic application via engineering the orbital texture of the bands. [Display omitted] [ABSTRACT FROM AUTHOR]

The spin Hall conductivity (SHC) and anomalous Hall conductivity (AHC) in about 120 full Heusler compounds are calculated using the density functional theory in a high-throughput way. The electronic structures are mapped to the Wannier basis and the linear response theory is used to get the conductivity. Our results show that the mechanism under the SHC or AHC cannot be simply related to the valence electron numbers or atomic weights. It is related to the very details of the electronic structures, which can only be obtained by calculations. A high-throughput calculation is efficient to screen out the desired materials. According to our present results, Rh _2 MnAl and Cu _2 CoSn, as well as Co _2 MnAl and Co _2 MnGa are candidates in spintronic materials regarding their high SHC and AHC values, which can benefit the spin-torque-driven nanodevices.

Thermal Hall conductivity κ x y and Hall spin conductivity σ x y in the nearest-neighbors antiferromagnetic Heisenberg model on kagome lattice with out-of-plane Dzyaloshinskii–Moriya interaction (DMI), which has been an active area of study in condensed matter physics, are studied using the linear spin-wave theory. We analyze the effect of this coupling on the behavior of κ x y as well as σ x y as well. For all cases analyzed, the behavior of κ x y and σ x y as a function of temperature T is analyzed where the behavior obtained for T finite, being due to the magnons thermally excited. We get a strong effect of temperature and DMI interaction on the behavior of both conductivities. • The thermal Hall conductivity and spin Hall conductivity are calculated. • The behavior of conductivities as a function of temperature is analyzed. • The effect of Dzyaloshinskii–Moriya interaction and temperature on conductivities are analyzed. [ABSTRACT FROM AUTHOR]

Magnetization manipulation caused by spin–orbit torque is one of the central themes investigated in spintronics domain. The spin–orbit torque efficiencies can be manoeuvred by application of mechanical strain. In this direction, this study furthers the effort in understanding the evolution of spin–orbit torque efficiencies in mechanically strained ferromagnet (FM)/heavy metal(HM) (Ni 81 Fe 19 /Pt) bi-layer films on flexible kapton substrate, by the use of spin torque ferromagnetic resonance (ST-FMR) measurement technique. We report a tensile strain induced enhancement in damping-like and field-like spin–orbit torque efficiencies. The effective damping-like spin torque conductivity increased by 42% on the application of 0.312% tensile strain, which is encouraging from the magnetization switching application point of view. In order to investigate the driving factors behind the enhanced damping-like spin torque conductivity, ab-initio calculations were also carried out. Our findings provide insights into the workings of strain in FM/HM bi-layer stack and is a step forward in the implementation of flexible spintronics devices. • ST-FMR measurement of Py/Pt stack on strained flexible substrate • Strain induced enhancement in damping and field-like spin–orbit torque efficiencies • Significant role of interface in enhancement of spin–orbit torque efficiencies [ABSTRACT FROM AUTHOR]

Based on the Kubo formula approach, the spin Hall conductivity (SHC) of a two-dimensional (2D) Rashba s-wave superconductor in the presence of nonmagnetic impurities is calculated. We will show that by increasing the superconducting gap, the SHC decreases monotonically to zero, while by decreasing the concentration of impurities at zero gap, the SHC closes to the clean limit universal value − e 8 π . As a function of the impurity relaxation rate τ at T c = 0.1 and γ = 0.01 ( γ is the spin–orbit coupling in unit of eV · m), we will show that in the dirty limit ( τ → 0) the SHC vanishes, and by increasing the relaxation time ( τ → ∞) the SHC depends on the value of superconducting gap ( Δ = 1.76 T c 1 − T T c ), is changed from zero for full gap to − e 8 π in zero gap. At low temperatures, the SHC goes to zero exponentially and near the critical temperature depending on the concentration of the scattering centers, the SHC will tend to the value of normal state. We will also show that the SHC is independent of spin–orbit coupling ( γ ) in the clean limit. [ABSTRACT FROM AUTHOR]

Spin-orbit torques (SOTs) generated by magnetic materials have prompted a surge of interest in low-power spintronics. In this context, rare-earth doped magnetic alloys are the ideal candidate due to the low symmetry and large spin-orbit coupling. Here, we present a study on SOTs generated by ferrimagnetic FeCoTb alloys in permalloy (Ni 80 Fe 20 , Py)/Cu/FeCoTb spin valve structures, showing high-efficient damping-like and field-like torques. Crucially, the spin Hall conductivity of FeCoTb is up to 6.32 × 105 (ℏ/2e) Ω−1m−1, larger than that in conventional heavy metals. By controlling the magnetic configuration of the spin valve structure, the magnetization dependent behavior of the SOTs is achieved, which may origin from the anomalous Hall effect of FeCoTb dominated by Tb magnetization. Our results demonstrate great prospects of ferrimagnetic materials for low-power spintronic applications. • Both high-efficient damping-like and field-like spin-orbit torques are achieved in ferromagnetic FeCoTb alloys. • A large spin Hall conductivity (∼6 × 105 (ℏ/2e) Ω−1m−1) is demonstrated. • Spin orbit torques in FeCoTb show the magnetization dependent behavior. [ABSTRACT FROM AUTHOR]

Spintronics is an emerging form of electronics based on the electrons' spin degree of freedom for which materials with robust half-metallic ferromagnet character are very attractive. Here we determine the structural stability, electronic, magnetic, and mechanical properties of the half-Heusler (hH) compound CoFeGe, in particular also in its cubic form. The first-principles calculations suggest that the electronic structure is robust with 100% spin polarization at the Fermi level under hydrostatic pressure and uni-axial strain. Both the longitudinal and Hall current polarization are calculated and the longitudinal current polarization (PL) is found to be>99%and extremely robust under uniform pressure and uni-axial strain. The anomalous Hall conductivity and spin Hall conductivity of hH cubic CoFeGe ( c -CoFeGe) are found to be∼-100S cm -1 and∼39 ℏ/eS cm -1 , respectively. Moreover, the Curie temperature of the alloy is calculated to be ∼524 K with a 3μBmagnetic moment. Lastly, the calculated mechanical properties indicate that c -CoFeGe is ductile and mechanically stable with a bulk modulus of ≈154 GPa. Overall, this analysis reveals that cubic CoFeGe is a robust half-metallic ferromagnet and an interesting material for spintronic applications., (© 2023 IOP Publishing Ltd.)

Spin Hall effect (SHE) is highly promising for future spintronic applications. Using ab initio calculations, we predict that the hexagonal layered material Pt 2 B exhibits a giant intrinsic SHE with an intrinsic spin Hall conductivity (SHC) of 2159 (ħ / e) S/cm, which can reach its maximum value of 2274 (ħ / e) S/cm at 0.04 eV above the intrinsic Fermi level. The large SHC mainly comes from the contributions of the two occupied bands below the Fermi level, and the energy difference between the occupied and unoccupied states determines the energy position of the maximal SHC. Pt 2 B's spin Hall angle (SHA) is of the same order as pure metal Pt. Our finds suggest that Pt 2 B is a fascinating material for producing pure spin current. • Pt 2 B could be a ideal system for achieving large SHC. It has an intrinsic SHC σ x y z as large as 2159 (ħ / e) S/cm. • The large SHC mainly come from the contribution of the two occupied bands below the Fermi level, and the energy difference between occupied and unoccupied states determines the energy position of maximal SHC. • The bands around the Fermi level do not have the SOC-induced anti-cross. Therefore, the mechanism of the large SHC of Pt 2 B is different from many previous reported materials. [ABSTRACT FROM AUTHOR]

We investigate the spin Hall conductivity σ of a clean 2D electron gas formed in a two-subband well. We determine σ as arising from the inter-subband induced spin–orbit (SO) coupling η (Calsaverini et al., Phys. Rev. B 78:155313, ) via a linear-response approach due to Rashba. By self-consistently calculating η for realistic wells, we find that σ presents a non-monotonic (and non-universal) behavior and a sign change as the Fermi energy varies between the subband edges. Although our σ is very small (i.e., ≪ `` e/4 π″), it is non-zero as opposed to linear-in- k SO models. [ABSTRACT FROM AUTHOR]

It is generally believed that conductivity plateaus can only exist in the insulators with topological nontrivial bulk occupied states. Such rule exhibits in two-dimensional quantum (anomalous) Hall effect, quantum spin Hall effect, and three-dimensional topological insulators. In this work, we propose spin Hall conductivity (SHC) plateau can be formed in three-dimensional metallic materials with triply degenerate points around the Fermi level. With the help of a four-band k ⋅ p model, we prove that SHC plateaus can be formed between | 3 2 , ± 3 2 〉 and | 1 2 , ± 1 2 〉 states of a metallic systems. Our further ab initio calculations reveal that a nearly ideal SHC plateau exhibits in an experimentally synthesized TaN. The plateau width reaches up to 0.55 eV, hoping to work at high temperatures. The electrical conductivity tensors of TaN indicates that its spin Hall angle reaches -0.57, which is larger than many previous reported materials and makes it an excellent candidate to produce stable spin current. • Spin Hall conductivity plateau can form in a semimetal with triply degenerate points. • TaN can achieve such SHC plateau. • This work paves a significance way for the application of SHE in real devices. [ABSTRACT FROM AUTHOR]

The fascinating electronic and optoelectronic properties of freestanding graphene and the possible inclusion of novel two-dimensional (2D) systems in silicon-based electronics have driven the search for atomic layers consisting of other group-IV elements Si, Ge, Sn, and Pb, which form similar hexagonal lattices and are isoelectronic to graphene. The resulting 2D crystals silicene, germanene, stanene and plumbene, referred as Xenes, but also their functionalized counterparts, e.g. the hydrogenated sheet crystals, named as Xanes, silicane, germanane, and stanane, are in the focus of this review article. In addition, halogenated Xenes are investigated. The consequences of the larger atomic radii on the atomic geometry, the energetic stability, and possible epitaxial preparations are discussed. In the case of honeycomb atomic arrangements, the low-energy electronic excitations are ruled by almost linear bands. Spin–orbit coupling opens small gaps leading to Dirac fermions with finite effective masses. The linear bands give rise to an absorbance of the Xenes determined by the finestructure constant in the long-wavelength regime. While for vanishing photon energies the excitonic influence is still an open question, saddle-point excitons and excitons at M 0 van Hove singularities appear at higher frequencies. After opening substantial fundamental gaps by hydrogenation, the absorption edges of the Xanes, silicane, germanane, and stanane, are dominated by bound excitons with extremely large binding energies. Other chemical functionalizations, but also vertical electric fields, yield electronic structures ranging from topological to trivial insulators. Even a quantum spin Hall phase is predicted at room temperature. The topological character and the possible quantization of the spin Hall conductivity are studied versus gap inversion, chemical functionalization, and Rashba spin–orbit interaction. The drastic changes of the electronic properties of Xenes with chemical functionalization, interaction with the substrate, and external perturbations, open future opportunities for tailoring fundamental properties and, therefore, interesting applications in novel electronic and optoelectronic nanodevices. [ABSTRACT FROM AUTHOR]

• Enhancement of spin Hall conductivity for Cu 40 W 60 |Fe by 120 % compared to α-W|Fe. • The ratio of spin Hall angle to damping was found to be reduced by a factor four. • Cu 40 W 60 |Fe is a promising candidate for energy efficient spintronic applications. We report on the enhancement of the spin Hall conductivity in tungsten by alloying with copper, measured by using the spin-torque ferromagnetic resonance technique. The alloying leads to an increase in spin-dependent scattering events and results in an enhancement of the contributing extrinsic spin Hall effects. The measured damping property shows a slight increase with higher tungsten concentration, due to spin current losses from the ferromagnetic layer into the tungsten-copper alloy. At a tungsten concentration of 60%, the spin Hall conductivity reaches a maximum of 3.68 ± 0.68 × 10 5 Ω - 1 m - 1 , corresponding to an enhancement of 120% compared to the pure tungsten sample. At the same concentration, the ratio of the spin Hall angle to the damping of the ferromagnetic layer, which offers a quick estimation for the critical switching current density, is found to be four times smaller as compared to pure tungsten. [ABSTRACT FROM AUTHOR]

Noble metal Pt with the face-centered-cubic structure is distorted to tetragonal and orthorhombic structures in order to mimic thin films grown on flexible substrates and bending. The electronic structures from the fully relativistic treatment of the kinetic terms were obtained and followed by projecting the extensive states into the localized Wannier orbitals with a minimum basis. The spin Hall conductivity (SHC) was then obtained with the help of the concept of the Berry curvature. We find that tensile strains in-plane can enhance the SHC while the compressive ones reduce the σ x y z component of the SHC. The variation of SHC can be as large as 8.6% for every 1% of the strains. Our work shows the possibility of tuning the SHC in metals, which can be utilized in spintronic devices. • The spin-to-charge conversion efficiency in Pt thin films can be enhanced by deformations. • The sensitivity of the spin Hall conductivity can be as large as 8.6% for every 1% of strains. • The underlying mechanism is the electronic band deformations. [ABSTRACT FROM AUTHOR]

Manipulation of magnetization by electric-current-induced spin-orbit torque (SOT) is of great importance for spintronic applications because of its merits in energy-efficient and high-speed operation. An ideal material for SOT applications should possess high charge-spin conversion efficiency and high electrical conductivity. Recently, transition metal dichalcogenides (TMDs) emerge as intriguing platforms for SOT study because of their controllability in spin-orbit coupling, conductivity, and energy band topology. Although TMDs show great potentials in SOT applications, the present study is restricted to the mechanically exfoliated samples with small sizes and relatively low conductivities. Here, a manufacturable recipe is developed to fabricate large-area thin films of PtTe 2 , a type-II Dirac semimetal, to study their capability of generating SOT. Large SOT efficiency together with high conductivity results in a giant spin Hall conductivity of PtTe 2 thin films, which is the largest value among the presently reported TMDs. It is further demonstrated that the SOT from PtTe 2 layer can switch a perpendicularly magnetized CoTb layer efficiently. This work paves the way for employing PtTe 2 -like TMDs for wafer-scale spintronic device applications., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Despite their great promise for providing a pathway for very efficient and fast manipulation of magnetization, spin‐orbit torque (SOT) operations are currently energy inefficient due to a low damping‐like SOT efficiency per unit current bias, and/or the very high resistivity of the spin Hall materials. This work reports an advantageous spin Hall material, Pd1−xPtx, which combines a low resistivity with a giant spin Hall effect as evidenced with three independent SOT ferromagnetic detectors. The optimal Pd0.25Pt0.75 alloy has a giant internal spin Hall ratio of >0.60 (damping‐like SOT efficiency of ≈0.26 for all three ferromagnets) and a low resistivity of ≈57.5 µΩ cm at a 4 nm thickness. Moreover, it is found that the Dzyaloshinskii–Moriya interaction (DMI), the key ingredient for the manipulation of chiral spin arrangements (e.g., magnetic skyrmions and chiral domain walls), is considerably strong at the Pd1−xPtx/Fe0.6Co0.2B0.2 interface when compared to that at Ta/Fe0.6Co0.2B0.2 or W/Fe0.6Co0.2B0.2 interfaces and can be tuned by a factor of 5 through control of the interfacial spin‐orbital coupling via the heavy metal composition. This work establishes a very effective spin current generator that combines a notably high energy efficiency with a very strong and tunable DMI for advanced chiral spintronics and spin torque applications. [ABSTRACT FROM AUTHOR]

Spin-orbit torques (SOT) in thin film heterostructures originate from strong spin-orbit interactions (SOI) that, in the bulk, generate a spin current due either to extrinsic spin-dependent, skew, or/and side-jump scattering or to intrinsic Berry curvature in the conduction bands. While most SOT studies have focused on materials with heavy metal components, the oxide perovskite SrRuO 3 has been predicted to have a pronounced Berry curvature. Through quantification of its spin current by the SOT exerted on an adjacent Co ferromagnetic layer, we determine that SrRuO 3 has a strongly temperature ( T)-dependent spin Hall conductivity σ SH , increasing with the electrical conductivity, consistent with expected behavior of the intrinsic effect in the "dirty metal" regime. σ SH is very high at low T, e.g., σ SH > (ℏ/2 e)3 × 10 5 Ω -1 m -1 at 60 K, and is largely unaffected by the SrRuO 3 ferromagnetic transition at T c ≈ 150 K, which agrees with a recent theoretical determination that the intrinsic spin Hall effect is magnetization independent. Below T c smaller nonstandard SOT components also develop associated with the magnetism of the oxide. Our results are consistent with the degree of RuO 6 octahedral tilt being correlated with the strength of the SOI in this complex oxide, as predicted by recent theoretical work on strontium iridate. These results establish SrRuO 3 as a very promising candidate material for implementing strong spintronics functionalities in oxide electronics.

There has been considerable interest in spin-orbit torques for the purpose of manipulating the magnetization of ferromagnetic elements for spintronic technologies. Spin-orbit torques are derived from spin currents created from charge currents in materials with significant spin-orbit coupling that propagate into an adjacent ferromagnetic material. A key challenge is to identify materials that exhibit large spin Hall angles, that is, efficient charge-to-spin current conversion. Using spin torque ferromagnetic resonance, we report the observation of a giant spin Hall angle [Formula: see text] of up to ~0.35 in (001)-oriented single-crystalline antiferromagnetic IrMn 3 thin films, coupled to ferromagnetic permalloy layers, and a [Formula: see text] that is about three times smaller in (111)-oriented films. For (001)-oriented samples, we show that the magnitude of [Formula: see text] can be significantly changed by manipulating the populations of various antiferromagnetic domains through perpendicular field annealing. We identify two distinct mechanisms that contribute to [Formula: see text]: the first mechanism, which is facet-independent, arises from conventional bulk spin-dependent scattering within the IrMn 3 layer, and the second intrinsic mechanism is derived from the unconventional antiferromagnetic structure of IrMn 3 . Using ab initio calculations, we show that the triangular magnetic structure of IrMn 3 gives rise to a substantial intrinsic spin Hall conductivity that is much larger for the (001) than for the (111) orientation, consistent with our experimental findings.