Anisotropic magnetic-field-induced phase transition in MnAs nanoribbons

F. FERNANDEZ BALDIS, M. SIRENA; L.B. STEREN; V. H. ETGENS, M. EDDRIEF; C. ULYSSE, G. FAINI,

APPLIED PHYSICS LETTERS

AMER INST PHYSICS

Lugar: New York; Año: 2015 vol. 107 p. 12407 - 12411

0003-6951

MnAs thin films are known to present a phase coexistence of regularly arranged ferromagnetic ( and paramagnetic () stripes below the Curie temperature when grown onto GaAs(100) substrates. The observation of the effect in nanostructures whose sizes matched the characteristic length of the / arrays allowed us to tune the phase coexistence regime by changing different parameters. In this letter, we report the observation of a magneto-structural phase transition induced by magnetic field on MnAs nanoribbons below the Curie temperature. A transformation of high-resistance paramagnetic regions into low-resistance ferromagnetic ones is observed above temperature-dependent critical magnetic fields. The phenomenon is hysteretic, highly anisotropic and size dependent.