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 – for example in magnons or pure spin currents – 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 ‘beyond CMOS’ 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, BaPb_1-xBi_xO₃ / La_0.7Sr_0.3MnO₃ (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 – 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.