Large spin Hall angle in vanadium film

Abstract

We report a large spin Hall angle observed in vanadium films sputter-grown at room temperature, which have small grain size and consist of a mixture of body centered tetragonal (bct) and body centered cubic (bcc) structures. The spin Hall angle is as large as θ V = −0.071 ± 0.003, comparable to that of platinum, θ Pt = 0.076 ± 0.007, and is much larger than that of bcc V film grown at 400 °C, θ V_bcc = −0.012 ± 0.002. Similar to β-tantalum and β-tungsten, the sputter-grown V films also have a high resistivity of more than 200 μΩ∙cm. Surprisingly, the spin diffusion length is still long at 16.3 nm. This finding not only indicates that specific crystalline structure can lead to a large spin Hall effect but also suggests 3d light metals should not be ruled out in the search for materials with large spin Hall angle.

Variable spin-charge conversion across metal-insulator transition

“…2f, the magnitude of V SP varies negligibly with increasing temperature in Pt/YIG sample, in sharp contrast to the results from VO 2 samples (Supplementary Note 5). Moreover, we note that V SP exhibits opposite signs for Pt and VO 2 samples under the same measurement configuration, indicating that VO 2 has a negative spin Hall angle, the same as pure metallic vanadium 9,24 .…”

Gigantic intrinsic orbital Hall effects in weakly spin-orbit coupled metals

“…This could explain the large SHAs observed from experiments on many 3d transition metals. [26][27][28][29][30][31] Our finding not only enriches understanding of the intrinsic OHE and SHE, but also widens material choice to weak SOC materials for spintronics. Moreover, our microscopic analysis based on the electronic band structure provides a route to enhancing these effects, i.e.…”

“…22 Most studies on the SHE so far have focused on 4d and 5d transition metals because large SOC in these materials tends to generate large SHE. [11][12][13][14][15][16] For 3d transition metals, on the other hand, theoretical study is limited 14 despite the fact that several experiments have reported that 3d transition metals such as V, 26 Cr, 27 Ni, 28 and Py 29 exhibit large SHAs. This motivates us to study the OHE and SHE in 3d transition metals.…”

Characterization and Manipulation of Spin Orbit Torque in Magnetic Heterostructures

“…Since θ SH is strongly correlated with the material atomic number, various HMs, such as Pt, Ta, W, V, Ir, and Hf, have been explored for SOT study . Among these materials, Pt is the most well studied, and it is found of a large positive SHA.…”