Magneto-transport in MnAs/GaAs(100) nano-ribbons

F. FERNANDEZ BALDIS, M. SIRENA, L.B. STEREN, M. TORTAROLO, M. SACCHI, A. LOCATELLI, O. MENTES, , B. SANTOS BURGOS, V.H. ETGENS

Rodas

Conferencia; JEMS 2013; 2013

JEMS

Hybrid metal/semiconductor systems are interesting in spintronics. In particular, MnAs is a magnetic metal that grows epitaxially on the semiconductor GaAs. A lot of work has been made towards the understanding of charge-transport and magnetism in these systems[1]. MnAs presents a magneto-structural first order phase transition at TC40ºC, the low-temperature hexagonal ferromagnetic structure  turns into an orthorhombic paramagnetic one . Films of MnAs/GaAs(100) present - phases coexistance from 10ºC to 50ºC due to strains induced by the substrate on the film. Previous work with nano-ribbons showed a dependence of the magnetic order with the confinement orientation and sizes, also with the temperature [2],[3]. Here we will present charge-transport measurements in MnAs/GaAs(100) nano-ribbons of 0.5m and 0.25m width, 20m large, and 30nm, 50nm, 140nm, and 300nm thickness. Nano-ribbons and contacts were patterned combining e-beam and optical litography. The results of the Hall-effect and magneto-resistance measurements performed at different temperatures allow us to investigate the charge carriers nature and the dominant transport mechanisms of the system.