Large spin Hall angle in vanadium film

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 theta(V) = -0.071 +/- 0.003, comparable to that of platinum, theta(Pt) = 0.076 +/- 0.007, and is much larger than that of bcc V film grown at 400 degrees C, theta(V) (bcc) = -0.012 +/- 0.002. Similar to beta-tantalum and beta-tungsten, the sputter-grown V films also have a high resistivity of more than 200 mu Omega.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.