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Title: Selective-area growth and magnetic characterization of MnAs/AlGaAs nanoclusters on insulating Al{sub 2}O{sub 3} layers crystallized on Si(111) substrates

We report on selective-area metal-organic vapor phase epitaxy and magnetic characterization of coupled MnAs/AlGaAs nanoclusters formed on thin Al{sub 2}O{sub 3} insulating layers crystallized on Si(111) substrates. Cross-sectional transmission electron microscopy reveals that poly-crystalline γ-Al{sub 2}O{sub 3} grains are formed after an annealing treatment of the amorphous Al{sub 2}O{sub 3} layers deposited by atomic layer deposition on Si(111) substrates. The 〈111〉 direction of the γ-Al{sub 2}O{sub 3} grains tends to be oriented approximately parallel to the 〈111〉 direction of the Si substrate. We observe that hexagonal MnAs nanoclusters on AlGaAs buffer layers grown by selective-area metal-organic vapor phase epitaxy on partially SiO{sub 2}-masked Al{sub 2}O{sub 3} insulator crystallized on Si(111) substrates are oriented with the c-axis along the 〈111〉 direction of the substrates, but exhibit a random in-plane orientation. A likely reason is the random orientation of the poly-crystalline γ-Al{sub 2}O{sub 3} grains in the Al{sub 2}O{sub 3} layer plane. Magnetic force microscopy studies at room temperature reveal that arrangements of coupled MnAs nanoclusters exhibit a complex magnetic domain structure. Such arrangements of coupled MnAs nanoclusters may also show magnetic random telegraph noise, i.e., jumps between two discrete resistance levels, in a certain temperature range, which can be explained bymore » thermally activated changes of the complex magnetic structure of the nanocluster arrangements.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [2]
  1. Research Center for Integrated Quantum Electronics, Hokkaido University, North 13 West 8, Sapporo 060-8628 (Japan)
  2. Institute of Experimental Physics I, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)
  3. (Germany)
Publication Date:
OSTI Identifier:
22489373
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 108; Journal Issue: 4; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALUMINIUM ARSENIDES; ALUMINIUM OXIDES; ANNEALING; ATOMIC FORCE MICROSCOPY; DOMAIN STRUCTURE; GALLIUM ARSENIDES; LAYERS; MAGNETIC FIELDS; MANGANESE ARSENIDES; NANOSTRUCTURES; ORGANOMETALLIC COMPOUNDS; RANDOMNESS; SILICON OXIDES; SUBSTRATES; TEMPERATURE RANGE 0273-0400 K; TRANSMISSION ELECTRON MICROSCOPY; VAPOR PHASE EPITAXY