Effect of Optical Spin Injection on Ferromagnetically Coupled Mn Spins in the III-V Magnetic Alloy Semiconductor [Formula presented]

Abstract

We report on the new type of photoinduced magnetization in ferromagnetic [Formula presented] thin films. Optically generated spin-polarized holes change the orientation of ferromagnetically coupled Mn spins and cause a large change in magnetization, being [Formula presented] of the saturation magnetization, without the application of a magnetic field. The memorization effect has also been found as a trace after the photoinduced magnetization. The observed results suggest that a small amount of nonequilibrium carrier spins can cause collective rotation of Mn spins presumably through the [Formula presented] exchange interaction. © 2002 The American Physical Society.