Electrical detection of Spin Hall effect in Tungsten films using a compact device geometry

Direct detection of Spin Hall Effect (SHE) using electrical schemes continues to be an experimental challenge as there is no electrical voltage associated with the accumulation of electron spins of opposite signs at the edges of a standard Hall bar sample. We present a simple yet elegant measurement scheme that allows detection of spin accumulation using the well known concepts of non-local detection proposed by Johnson and Silsbee. We fabricated devices with pairs of voltage leads consisting of a ferromagnet (FM: Co or Py) and a normal metal (NM: Cu) suitably placed in contact with one of the spin accumulation edge of Tungsten (W) bar shaped films, so that other competing effects like ordinary Hall effect and magnetoresistance are minimised. We show that voltage difference measured between the FM and NM leads are a manifestation of the spin accumulation due to SHE. We present detailed temperature and magnetic field dependent study of the spin Hall conductivity extracted from the spin accumulation voltage.