Efficient and controlled manipulation of the spin Hall angle in Pt–Ag interface

The spin Hall angle (θSH) is a measure of efficiency of the spin-to-charge conversion process. In this paper, we report that it is possible to control the θSH by engineering an array of Ag microdisks by direct write laser lithography in multilayers formed by Pt/Ag/Pt/Py (Ni20Fe80) grown on Si/SiO2 substrates. The investigation of the spin-to-charge conversion was made using spin pumping measurements, and it was shown that as the number of disks increases, the current generated by the spin pumping also increases. This result demonstrates that it is possible to tune the spin Hall angle by changing the number of the Ag microdisks while keeping their size and shape fixed.