Giant Room Temperature Spin Hall Effect in BaPb_1-xBi_xO₃Thin Film Heterostructures

BaPb_1-xBi_xO₃ (BPBO) is a superconductor with strong spin-orbit coupling and a Tc of 11K at optimal doping ( x=0.25 ) [1], bounded by metallic BaPbO₃ (x=0) and charge density wave insulator BaBiO₃ (x=1) in its phase diagram. We study room temperature charge to spin conversion in BPBO/Permalloy thin film heterostructures by spin-torque ferromagnetic resonance, finding a large spin Hall angle in BPBO (x=0.25). The much smaller spin Hall angle we observe in the parent BaPbO₃ (x=0) indicates a significant role of Bi in engineering the spintronic properties of this system. This work highlights the potential of BPBO and other phase-competition superconductors for superconducting spintronics.