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Title: Oxide shell reduction and magnetic property changes in core-shell Fe nanoclusters under ion irradiation

Ion irradiation effects are studied on the Fe-based core-shell nanocluster (NC) films with core as Fe and shell as Fe{sub 3}O{sub 4}/Fe{sub 3}N. These NC films were deposited on Si substrates to thickness of ∼0.5 μm using a NC deposition system. The films were irradiated at room temperature with 5.5 MeV Si{sup 2+} ions to ion fluences of 10{sup 15} and 10{sup 16} ions/cm{sup 2}. It is found that the irradiation induces grain growth, Fe valence reduction in the shell, and crystallization or growth of Fe{sub 3}N. The film retained its Fe-core and its ferromagnetic properties after irradiation. The nature and mechanism of oxide shell reduction and composition dependence after irradiation were studied by synthesizing additional NC films of Fe{sub 3}O{sub 4} and FeO + Fe{sub 3}N and irradiating them under the same conditions. The presence of nanocrystalline Fe is found to be a major factor for the oxide shell reduction. The surface morphologies of these films show dramatic changes in the microstructures due to cluster growth and agglomeration as a result of ion irradiation.
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Department of Physics, University of Idaho, Moscow, Idaho 83844 (United States)
  2. Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352 (United States)
  3. School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164 (United States)
Publication Date:
OSTI Identifier:
22273878
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 17; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; CRYSTALLIZATION; CRYSTALS; GRAIN GROWTH; INTERFACES; ION BEAMS; IRON; IRON NITRIDES; IRON OXIDES; IRRADIATION; MAGNETIC PROPERTIES; MICROSTRUCTURE; MORPHOLOGY; NANOSTRUCTURES; PHYSICAL RADIATION EFFECTS; SILICON IONS; SUBSTRATES; SURFACES; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; VALENCE