Spin Hall effects from mesoscopic ferromagnetic NiFe thin films

The spin Hall effect (SHE) and inverse spin Hall effect (ISHE) have been explored primarily in nonmagnetic heavy metals such as Pt. In this work, we probe SHE/ISHE from mesoscopic ferromagnetic NiFe (Py) films in nonlocal lateral structures. The structure consists of a Py spin injector/detector (F1), a Cu channel, and a second Py stripe (F2) where SHE/ISHE occurs. Low-resistance AlOx layers are placed at all interfaces. For SHE, a charge current passes through F2, and a nonlocal voltage is detected between F1 and Cu. For ISHE, a charge current is injected from F1 into Cu, and the nonlocal voltage is measured between two ends of F2. The in-plane magnetic field is applied perpendicular to F1/F2 stripes. For both measurements, the nonlocal signal for large positive field is different from that of large negative field owing to the SHE/ISHE. Using a simple model, the apparent spin Hall angle (assuming long Py spin diffusion length) of Py is estimated to be 0.010 at 295K and 0.017 at 4.5K.