Influence of dc bias currents on Co/Cu/Co nonlocal spin valves

The spin signals of three Co/Cu/Co nonlocal spin valves have been measured as a function of a dc bias current. Both increases and decreases of spin signals have been observed. The increase in spin signal is attributed to the redistribution of the injection current at a high current density. A shift in effective injection point up to similar to 100 nm is estimated. The decrease in spin signals is attributed to structural change of the materials and interfaces due to the prolonged exposure to a high-density current. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3123255]