Direct comparison of static and dynamic measurements of spin generation in a topological insulator thin film

Comparing spin transport parameters obtained by different measurement techniques can alleviate discrepancies in reported values and highlight the reliability of methods. Here, we directly compare the spin Hall coefficient (θSH) in molecular beam epitaxy grown films of (Bi1–xSbx)2Te3–ySey (BSTS, x = 0.58, y = 1) at room temperature using two complementary techniques: a static method using non-local voltage (NLV) measurements in BSTS Hall bars with DC charge current and a dynamic method using spin-torque ferromagnetic resonance (ST-FMR) measurement in BSTS/Ni80Fe20 heterostructures at GHz frequencies. We obtain comparable spin Hall coefficients in angular-dependent ST-FMR (θSH=4.7±1.1) and in NLV (θSH=2.8±0.6). The complex effects of ferromagnetic interfaces while determining spin Hall coefficients using static or dynamic techniques become evident by contrasting our results to the literature.