Nonlocal spin valves with thin Co electrodes for spin-transfer.

Cobalt/copper nonlocal spin valve devices with AlO_x barriers are fabricated for the purpose of spin-transfer with a pure spin current. The submicron planar device consists of a Co spin injector (F₁), a Co spin detector (F₂), and a Cu channel. The F₂ Co electrode is only 2.5 nm thick, but sizable nonlocal spin signals of 2–4 mΩ are measured at 4.2 K. The spin-transfer switching has been achieved with the assistance of a magnetic field. The magnetizations of F₁ and F₂ electrodes are set to an antiparallel state by sweeping the magnetic field. The magnetic field is then held at a value smaller but close to the switching field of F₂. A small dc current (0.1–1 mA) is sufficient to switch F₂ into being parallel with F₁. Analysis has been done to rule out possible artifacts due to Oersted fields. [ABSTRACT FROM AUTHOR]