Current-induced hysteretic switching and reversible transition of magnetization in spin-valve structures with current constraint paths in spacer layers

摘要

Current-induced magnetization dynamics has been investigated in circular spin-valvelike nanopillars (less than 100 nm in diameter) with a nano-oxide spacer layer. From the magnetoresistance measurements at room temperature, both the hysteretic switching and the reversible transition of the free layer magnetization between the parallel alignment and the antiparallel alignment are observed for current-perpendicular-to-the-plane bottom spin valves with nano-oxide spacer layer insertion. The findings.that may reveal the fundamentals of the spin-transfer torque effect indicate that out present understanding based on the phenomenological description of the spin-transfer torque is incomplete.