We systematically measure and analyze the spin diffusion length and the spin Hall effect in Pt with a wide range of conductivities using the spin absorption method in lateral spin valve devices. We observe a linear relation between the spin diffusion length and the conductivity, evidencing that the spin relaxation in Pt is governed by the Elliott-Yafet mechanism. We find a single intrinsic spin Hall conductivity ( =1600150  -1 cm -1 ) for Pt in the full range studied which is in good agreement with theory. For the first time we have obtained the crossover between the moderately dirty and the superclean scaling regimes of the spin Hall effect by tuning the conductivity. This is equivalent to that obtained for the anomalous Hall effect. Our results explain the spread of the spin Hall angle values in the literature and find a route to maximize this important parameter.Spin-orbit interaction is an essential ingredient in solid state physics [1,2] that has been gaining interest in the last decade due to the advantages it offers to exploit the coupling between spin and orbital momentum of electrons in spintronic devices, leading to the emerging field of spin-orbitronics [3]. The discovery of new charge-to-spin current conversion effects such as the spin Hall effect (SHE) [4,5,6,7], the Rashba-Edelstein effect (REE) [8,9,10] or the spin-momentum locking (SML) in topological insulators [11,12,13] is expanding the possibility to create and detect spin currents without using ferromagnets (FM) or magnetic fields. For instance, magnetization switching of ferromagnetic elements has been recently achieved with torques arising from SHE [14], REE [15] or SML [16], and new spindependent phenomena such as the spin Seebeck effect [17] or spin pumping [18] have been discovered by using SHE to detect spin currents.The SHE is thus the crucial effect behind this breakthrough. Although it was predicted theoretically by Dyakonov and Perel 45 years ago [1] and revisited by Hirsch in 1999 [4], it took a bit longer to observe the first direct experimental evidences in semiconductors [19] and metals [6,7,18]. The SHE in a non-magnet (NM) basically shares the same origin as the anomalous Hall effect (AHE) in FMs: in both effects, the spin-orbit coupling generates the opposite deflection of the spin-up and spin-down electrons in a charge current, leading to a

We report measurements of a new type of magnetoresistance in Pt and Ta thin films. The spin accumulation created at the surfaces of the film by the spin Hall effect decreases in a magnetic field because of the Hanle effect, resulting in an increase of the electrical resistance as predicted by Dyakonov [PRL 99, 126601 (2007)]. The angular dependence of this magnetoresistance resembles the recently discovered spin Hall magnetoresistance in Pt/Y 3 Fe 5 O 12 bilayers, although the presence of a ferromagnetic insulator is not required. We show that this Hanle magnetoresistance is an alternative, simple way to quantitatively study the coupling between charge and spin currents in metals with strong spin-orbit coupling.Spin-orbit interaction is an essential ingredient in materials and interfaces, offering the possibility to exploit the coupling between spin and orbital degrees of freedom of electrons in spintronic devices [1,2]. Of utmost importance are the spin Hall (SHE) and inverse spin Hall (ISHE) effects, which convert charge currents into transverse spin currents and vice versa, allowing us to create and detect spin currents in materials with strong spin-orbit coupling (SOC) [3][4][5][6][7][8]. In this framework, a new type of magnetoresistance (MR), spin Hall magnetoresistance (SMR), was discovered in nonmagnetic (NM) metal/ferromagnetic insulator (FMI) bilayers [9][10][11][12][13][14][15][16]. SMR arises from the simultaneous effect of SHE and ISHE in the NM layer -which leads to a decrease in its resistance-combined with the presence of a FMI at one of

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms PHYSICAL REVIEW B 91, 024402 (2015) We have studied the spin transport and the spin Hall effect as a function of temperature for platinum (Pt) and gold (Au) in lateral spin valve structures. First, by using the spin absorption technique, we extract the spin diffusion length of Pt and Au. Secondly, using the same devices, we have measured the spin Hall conductivity and analyzed its evolution with temperature to identify the dominant scattering mechanisms behind the spin Hall effect. This analysis confirms that the intrinsic mechanism dominates in Pt whereas extrinsic effects are more relevant in Au. Moreover, we identify and quantify the phonon-induced skew scattering. We show that this contribution to skew scattering becomes relevant in metals such as Au, with a low residual resistivity.

We report magnetoresistance measurements on thin Pt bars grown on epitaxial (001) and (111) CoFe2O4 (CFO) ferrimagnetic insulating films. The results can be described in terms of the recently discovered spin Hall magnetoresistance (SMR). The magnitude of the SMR depends on the interface preparation conditions, being optimal when Pt/CFO samples are prepared in situ, in a single process. The spin-mixing interface conductance, the key parameter governing SMR and other relevant spin-dependent phenomena such as spin pumping or spin Seebeck effect, is found to be different depending on the crystallographic orientation of CFO, highlighting the role of the composition and density of magnetic ions at the interface on spin mixing.Comment: 13 pages, 5 figure

The contributions to the spin relaxation in copper (Cu) nanowires are quantified by carefully analyzing measurements of both charge and spin transport in lateral spin valves as a function of temperature and thickness. The temperature dependence of the spin-flip scattering solely arises from the scattering with phonons, as in bulk Cu, whereas we identify grain boundaries as the main temperature-independent contribution of the defects in the nanowires. A puzzling maximum in the spin diffusion length of Cu at low temperatures is found, which can be explained by the presence of magnetic impurities. The results presented here suggest routes for improving spin transport in metallic nanostructures, otherwise limited by confinement effects.Comment: 10 pages, 4 figures, 1 tabl