Microstructure of (Ga,Mn)As/GaAs digital ferromagnetic heterostructures

Journal Article · Sun May 01 00:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1889225· OSTI ID:20713934

Kong, X; Trampert, A; Guo, X X; Kolovos-Vellianitis, D; Daeweritz, L; Ploog, K H ^[1]

---

1. Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin (Germany)

We report on the microstructure of (Ga,Mn)As digital ferromagnetic heterostructures grown on GaAs (001) substrates by low-temperature molecular-beam epitaxy. The Mn concentration and the As{sub 4}/Ga beam equivalent pressure (BEP) ratio are varied in the samples containing periods of Mn sheets separated by thin GaAs spacer layers. Transmission electron microscopy studies reveal that decreasing the Mn doping concentration and reducing the BEP ratio lead to smaller composition fluctuations of Mn and more homogeneous (Ga,Mn)As layers with abrupt interfaces. Planar defects are found as the dominant defect in these heterostructures and their density is related to the magnitude of the composition fluctuation. These defects show a noticeable anisotropy in the morphologic distribution parallel to the orthogonal [110] and [110] direction. Along the [110] direction, they are stacking faults, which are preferentially formed in V-shaped pairs and nucleate at the interfaces between (Ga,Mn)As and GaAs layers. Along the [110] direction, the planar defects are isolated thin twin lamellae. The character of the planar defects and their configuration are analyzed in detail.

• OSTI ID: 20713934
• Journal Information: Journal of Applied Physics, Vol. 97, Issue 9; Other Information: DOI: 10.1063/1.1889225; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
CRYSTAL GROWTH
FERROMAGNETIC MATERIALS
GALLIUM ARSENIDES
HETEROJUNCTIONS
IMPURITIES
INTERFACES
LAMELLAE
LAYERS
MAGNETIC SEMICONDUCTORS
MANGANESE ARSENIDES
MICROSTRUCTURE
MOLECULAR BEAM EPITAXY
NUCLEATION
ROUGHNESS
STACKING FAULTS
SUBSTRATES
TRANSMISSION ELECTRON MICROSCOPY