Spin transport in metal-oxide switching devices

Metal-oxide-based devices in which resistive switching occurs, often referred to as memristors or resistive-RAM (random oxide memory), show promise for use in technologically exciting applications such as high-density non-volatile memories, electronically reconfigurable logic, and neural networks. We report on electron spin transport through electrochemically precipitated copper filaments formed in TaO$_{x}$ memristive devices consisting of Co(60 nm)/TaO$_{x}$ (16nm)/Cu(5 nm)/Py(60 nm) with crossbar-type electrode geometry. These metal-oxide switching devices with ferromagnetic electrodes show memristive behavior having a typical OFF/ON resistance ratio of 10$^{5}$. Magnetoresistance measurements performed by sweeping an external magnetic field display evidence of spin transport in the low-resistance ON-state at 77 K. Spin transport vanishes in the OFF-state. These data are strong evidence that the fundamental switching mechanism in these metal-oxide devices is the creation of Cu filaments in the ON-state that completely span the 16 nm thick TaO$_{x}$ and form a continuous metallic conduction path. In addition to helping elucidate the conduction pathway in these intriguing structures, our findings can advance electronics combining spintronic and electronic functions.