Interface induced inverse spin Hall effect in bismuth/permalloy bilayer

Hou, D.*; Qiu, Z.*; Harii, Kazuya; Kajiwara, Yosuke*; Uchida, Kenichi*; Fujikawa, Yasunori*; Nakayama, Hiroyasu*; Yoshino, Tatsuro*; An, Toshu*; Ando, Kazuya*; Jin, X.*; Saito, Eiji

Inverse spin Hall effect has been investigated in bismuth(Bi)/permalloy(Py) bilayer films by using the spin pumping at room temperature. From the ferromagnetic-resonance-spectrum linewidth data, Bi is proved to be a good spin sink in our structure. We measured inverse spin Hall voltage and conductance of the Bi/Py bilayer and found that the inverse spin Hall current, , decreases with increasing the Bi thickness, which is in contrast to the former understanding in similar bilayer systems, e.g., Pt/Py. We constructed a model to explain the thickness dependence of quantitatively, in which spin transport modulation near Bi/Py interface is considered.