Spintronics is a promising field centered around next-generation devices that use electronic spin to store and manipulate information. Since there are no ohmic losses inherent in the transfer of spin â€“ for example in magnons or pure spin currents â€“ spintronic devices have the potential to be very energy efficient, and lots of efforts have been taken over the last few decades to apply spintronic principles to make â€˜beyond CMOSâ€™ devices. However, one of the major challenges in spintronics is to find material systems with efficient spin-to-charge conversion, and the lack of such model systems has kept practical, energy efficient spintronic applications from being realized. We propose a new pathway for discovering model systems with efficient spin-to-charge conversion in epitaxial oxide heterostructures. We present on one such system, BaPb1-xBixO3 / La0.7Sr0.3MnO3 (BPBO/LSMO), grown by pulsed laser deposition with excellent crystalline quality characterized by X-ray diffraction and TEM. Using spin-torque ferromagnetic resonance (STFMR) experiments, we measured a spin-orbit torque efficiency of 3 â€“ over an order of magnitude greater than typical spin-orbit coupled metals. We confirm this measurement with samples grown and measured across 3 different labs, along with transverse STFMR and Second Harmonic experiments (see Fig. 1). We also find an enhancement of the spin-orbit torque efficiency for thinner layers of BPBO, indicating that the epitaxial interface plays an important role in the generation of spin-orbit torques. With a better understanding of the role of the interface in spin-orbit torque generation, and by exploring similar complex oxide systems, we hope to find a model epitaxial oxide heterostructure that can be used for energy efficient spintronic applications.
We acknowledge SRC-ASCENT for funding support.