2014/06/27 by Aloyzas Siusys, Aloyzas Šiušys, Janusz Sadowski +8 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #Carbon Nanotubes in Composites #Epitaxy #Ferromagnetism #High-resolution transmission electron microscopy #Molecular beam epitaxy #Nanowire #Nanowire Synthesis and Applications #Raman scattering #Raman spectroscopy #Transmission electron microscopy #Wurtzite crystal structure #ZnO doping and properties #cond-mat.mtrl-sci
paper · pdf · doi:10.1021/nl500896d
published as Nano Letters 14, 4263 (2014) · 37 pages, 8 figures
openalex publication_date 2014/06/27 · arxiv created 2014/09/09 · arxiv updated 2015/06/22 · openalex created_date 2019/06/27 · openalex updated_date 2026/08/05
Structural and magnetic properties of (In,Ga)As-(Ga,Mn)As core-shell nanowires grown by molecular beam epitaxy on GaAs(111)B substrate with gold catalyst have been investigated. (In,Ga)As core nanowires were grown at high temperature (500 °C) whereas (Ga,Mn)As shells were deposited on the 11̅00 side facets of the cores at much lower temperature (220 °C). High-resolution transmission electron microscopy images and high spectral resolution Raman scattering data show that both the cores and the shells of the nanowires have wurtzite crystalline structure. Scanning and transmission electron microscopy observations show smooth (Ga,Mn)As shells containing 5% of Mn epitaxially deposited on (In,Ga)As cores containing about 10% of In without any misfit dislocations at the core-shell interface. With the In content in the (In,Ga)As cores larger than 5% the (In,Ga)As lattice parameter is higher than that of (Ga,Mn)As and the shell is in the tensile strain state. Elaborated magnetic studies indicate the presence of ferromagnetic coupling in (Ga,Mn)As shells at the temperatures in excess of 33 K. This coupling is maintained only in separated mesoscopic volumes resulting in an overall superparamagnetic behavior which gets blocked below ∼ 17 K.