Interfacial manipulation of spin-orbit torques in BaPb_1-xBi_xO₃/La_1-xSr_xMnO₃ system

The spin Hall effect (SHE) in a correlated electronic system can be used to apply a torque on the magnetization of an adjacent magnet, offering a promising candidate for energy efficient, nonvolatile data storage. Modifying the properties of the spin-current generating layer has provided tools with which the SHE can be controlled; however, few have studied how the interface between the magnet and the spin-current generating layer can be engineered to control the strength of a spin-orbit torque (SOT) onto the magnetization. Here, we synthesized BaPb_1-xBi_xO₃/La_1-xSr_xMnO₃ (BPBO/LSMO) heterostructures on SrTiO₃ substrates using pulsed laser deposition (PLD) to investigate how interfacial engineering can modify the strength of SOTs across the interface of the heterostructure. We modify the interface quality by manipulating PLD growth parameters and characterize the interface quality using transmission electron microscopy. We quantify the SOT strength and symmetry using spin-torque ferromagnetic resonance, illuminating the role of the interface in the strength of SOTs. With a better understanding of the role of the interface in utilizing the SHE, we will be better equipped to select for material systems that will excel in applications such as magnetic memory.