Lateral nonlocal spin-transfer structures with separately tailored polarizer and free-layer interfaces

Abstract

We investigate spin-transfer effects in mesoscopic lateral nonlocal structures. The structure consists of laterally separated spin polarizer and magnetic free layer bridged by a copper channel. The larger (300 nm × 80 nm) oxide interface on the polarizer reduces charge current density, and the small (80 nm × 80 nm) ohmic interface on the free layer draws a high-density spin current. Reversible and bistable switching of the 3 nm Ni81Fe19 free-layer, induced by a pure spin current, is observed between 5 K and 150 K. The interfacial critical charge current density required for switching is 1.5 × 107 A cm−2 at 5 K and ~6 × 106 A cm−2 between 100 K and 150 K. The ratio of spin current density to charge current density is estimated to be 0.19. The results demonstrate that lateral nonlocal spin-transfer structures can be potentially as efficient and robust as the nanopillar structures.