Memory Effect in the Photoinduced Femtosecond Rotation of Magnetization   in the Ferromagnetic Semiconductor GaMnAs
  We report a femtosecond response in photoinduced magnetization rotation in the ferromagnetic semiconductor GaMnAs, which allows for detection of a four-state magnetic memory at the femtosecond time scale. The temporal profile of this cooperative magnetization rotation exhibits a discontinuity that reveals two distinct temporal regimes, marked by the transition from a highly non-equilibrium, carrier-mediated regime within the first 200 fs, to a thermal, lattice-heating picosecond regime. 
J. Wang,(1) I. Cotoros,(1) X. Liu,(2) J. Chovan,(3) J. K. Furdyna,(2)   I. E. Perakis,(3) and D. S. Chemla (1) ((1) Material...