Evolution of the spin Hall effect in Pt nanowires: Size and temperature effects

We have studied the evolution of the Spin Hall Effect in the regime where the material size responsible for the spin accumulation is either smaller or larger than the spin diffusion length. Lateral spin valve structures with Pt insertions were successfully used to measure the spin absorption efficiency as well as the spin accumulation in Pt induced through the spin Hall effect. Under a constant applied current the results show a decrease of the spin accumulation signal is more pronounced as the Pt thickness exceeds the spin diffusion length. This implies that the spin accumulation originates from bulk scattering inside the Pt wire and the spin diffusion length limits the SHE. We have also analyzed the temperature variation of the spin hall conductivity to identify the dominant scattering mechanism.Comment: 4 pages, 4 figure

Magneto-thermoelectric effects mapping using tip-induced temperature gradient in atomic force microscopy

Mapping magneto-thermoelectric effects, such as the anomalous Nernst effect, are crucial to optimize devices that convert thermal energy to electric energy. In this article, we show the methodology to realize this based on a technique we recently established using atomic force microscopy, in which a tip contact on the surface locally creates the temperature gradient. We can map the non-magnetic Seebeck and anomalous Nernst effects separately by investigating the magnetic field dependence. The simulation based on a simple heat transfer model between the tip and sample quantitatively explains our results. We estimated the magnitude of the anomalous Nernst effect in permalloy from the experiment and simulation to be ∼0.10 μV/K