Experimental Verification of Comparability between Spin-Orbit and Spin-Diffusion Lengths

Abstract

We experimentally confirmed that the spin-orbit lengths of noble metals obtained from weak antilocalization measurements are comparable to the spin diffusion lengths determined from lateral spin valve ones. Even for metals with strong spin-orbit interactions such as Pt, we verified that the two methods gave comparable values which were much larger than those obtained from recent spin torque ferromagnetic resonance measurements. To give a further evidence for the comparability between the two length scales, we measured the disorder dependence of the spin-orbit length of copper by changing the thickness of the wire. The obtained spin-orbit length nicely follows a linear law as a function of the diffusion coefficient, clearly indicating that the Elliott-Yafet mechanism is dominant as in the case of the spin diffusion length.

Spin Torque Study of the Spin Hall Conductivity and Spin Diffusion Length in Platinum Thin Films with Varying Resistivity

“…Fast saturation of the damping at very thin Pt thicknesses has also been observed previously [22,37,38]. However, Liu et al [47] have recently pointed out that this very rapid attenuation is likely due to strong SML at the FM/Pt interface, and used a first principles calculation and data [61] from this measurement method to obtain 5.5 nm has been determined from a low temperature, 3-10 K, study of spin pumping in lateral spin valves [39,41] This work seems to resolve the controversy regarding the differences in the value of s λ for Pt as obtained from various spin Hall and other experiments, and demonstrates that the spin…”

Kondo physics in non-local metallic spin transport devices

“…This non-local geometry has enabled significant advances in the understanding of spin transport in metals [4][5][6][7][8][9][10][11][12][13][14][15][16]18,22,[24][25][26][27][28][29][30][31][32][33][34][35][36][37] , but has also highlighted serious discrepancies with theory. The primary example of the latter is the surprising non-monotonicity in the temperature (T) dependence of DR NL , and thus the deduced l N , in the transparent interface limit.…”

“…Remarkably, despite the maturity of metallic spintronics, there remain large gaps in our fundamental understanding of spin transport in metals, particularly with injection of spins across ferromagnet (FM)/nonmagnetic metal (NM) interfaces, and their subsequent diffusion and relaxation. Unresolved issues include the applicability of the widely employed Elliott-Yafet (E-Y) 3 spin relaxation mechanism [4][5][6][7][8][9][10] , the influence of defects, surfaces and interfaces on spin relaxation at nanoscopic dimensions 8,[11][12][13][14][15] , the importance of magnetic and spin-orbit scattering [16][17][18] and the accuracy of existing models [19][20][21][22][23] .…”

Nanomechanical detection of the spin Hall effect

“…Measurements and characterization of Θ SH have, as yet, been limited to methods based on optical, electrical, and magnetic effects, which require knowledge of Kerr rotation coupling, metallic interfaces, magnetic properties, and spin diffusion parameters to quantify Θ SH accurately [15,26]. As such, reported values of Θ SH span orders of magnitude for materials such as Pt and Pd [19,[27][28][29][30][31][32][33][34][35]. Open questions such as the dependence of Θ SH on growth conditions, film thickness, impurity level, frequency, and other systematic parameters must be addressed both experimentally and theoretically.…”