Size effects on the phase coexistence in MnAs/GaAs(001) ribbons

M. TORTAROLO; M. SIRENA; J. MILANO; L. B. STEREN; F. VIDAL; B. RACHE SALLES; V. H. ETGENS; M. EDDRIEF; G. FAINI; L. I. PIETRASANTA

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Año: 2010 p. 224406 - 224410

1098-0121

Size and orientation effects on the phase coexistence in MnAs/GaAs(001) microribbons were studied using magnetic force microscopy. The magnetostructural phase coexistence reported in MnAs thin films is also observed in the microribbons, even in the smallest ones. However, the stripe array of MnAs films is only preserved in the ribbons confined along the [0001] direction. Nevertheless, the configuration of the magnetoelastic domains is altered in the ribbons confined along the [112̅ 0] direction. In this last case, the micrometric ribbons exhibit a redistribution of the magnetoelastic phases owed to the relaxation of the epitaxial strains. The results are understood in terms of the anisotropic change in the lattice parameters at the magnetostructural transition.