Fast field induced domain wall dynamics in MnAs/GaAs films

M. TORTAROLO; L. THEVENARD; J. VON BARDELEBEN; C. GOURDON; M. EDDRIEF; V. ETGENS

Chicago

Conferencia; MMM/Intermag 2013, Chicago, EE.UU; 2013

IEEE

The possibility of storing information in magnetic domains separated by domain walls (DW) moving along domain tracks has stimulated a renewed interest in DW propagation in in-plane magnetized materials for spintronics[1]. Most studies are performed on Permalloy where high DW velocities (up to 1000 m s-1) can be achieved[2]. However it is well known that MnAs is a promising candidate for spintronics applications as it can be grown on different semiconductors[3]. Even though the domain wall (DW) dynamics in ferromagnetic films has been intensively studied during the last decades DW propagation in MnAs was studied only recently, and has been limited to the slow DW evolution (velocity ~ 30 m s-1) under application of a magnetic field close to the coercive field[4]. Field-induced domain wall (DW) dynamics was investigated in MnAs/GaAs(100) films by means of longitudinal Kerr microscopy and a field pulse technique. Saw-tooth type domains were observed in the studied temperature range. DW velocities up to 950 m s−1 were measured at 200 K and up to 540 m s−1 at 290 K, at the beginning of the nucleation of the non-ferromagnetic β phase within the ferromagnetic α phase. Different propagation regimes were observed depending on the magnitude of the Walker field compared to the depinning field, which depends on the progressive nucleation of an unordered β phase. The results are interpreted in the framework of the one-dimensional model (1D) for DW propagation[6].