62. Temperature evolution of magnetic phase coexistence in MnAs thin films

J. MILANO, L. B. STEREN A. H. V. REPETTO LLAMAZARES, V. GARCIA, M. MARANGOLO, M. EDDRIEF, V. H. ETGENS

APPLIED PHYSICS LETTERS

AMER INST PHYSICS

Año: 2008 vol. 92 p. 32503 - 32505

0003-6951

We report on the appearance of magnetic stripes in MnAs/GaAs(100) epilayers at temperatures well below the ferromagnetic transition of the system. The study has been performed by ferromagnetic resonance (FMR) experiments on MnAs epilayers grown on the (100) and (111) GaAs substrates. The FMR spectra of the MnAs/GaAs(100) samples at 180 K reveal the appearance of zones of different magnetic behaviors with respect to the low-temperature homogeneous ferromagnetic phase. The angular and the temperature dependences of the spectra serve us to detect the intergrowth of the nonmagnetic phase into the ferromagnetic phase at a very early stage of the process. The experimental data show that the paramagnetic phase nucleates in a self-arranged array of stripes in MnAs/GaAs(100) thin films while it grows randomly in the same films grown on GaAs(111).