Structure and magnetic properties of irradiated Fe-Fe oxide core-shell nanoclusters
- Pacific Northwest National Laboratory, 902 Battelle Blvd., PO Box 999, Richland, WA 99352 (United States)
- Department of Physics, University of Idaho, Moscow, ID 83844 (United States)
- Department of Physics, University of California, Davis, CA 95616 (United States)
A cluster deposition method was used to produce a film of loosely aggregated particles of Fe-Fe{sub 3}O{sub 4} coreshell nanoclusters with an 8 nm iron core size and 2 nm oxide shell thickness. The film of particles on a silicon substrate was irradiated with 5.5 MeV Si{sup 2+} ions to a fluence of 10{sup 16} cm{sup -2} near room temperature, and computer simulations based on the SRIM (Stopping and Range of Ions in Matter) code show that the implanted Si species stops near the filmsubstrate interface. The ion irradiation creates a structural change in the film with corresponding chemical and magnetic changes. X-ray diffraction shows that the core size and chemistry stay the same but the shell becomes FeO that grows to a thickness of 17 nm. Helium ion microscopy shows that the previously separate particles have densified into a nearly continuous film. Major loop magnetic hysteresis measurements show a decrease in saturation magnetization that we attribute to the presence of the antiferromagnetic (AFM) FeO shell. First-order reversal curve measurements on the irradiated film performed with a vibrating sample magnetometer show that the AFM shell prevents the particles from interacting magnetically, leading to low coercivity from the iron core and little bias field from the core interactions. These results, and others reported previously on different compositions (Fe{sub 3}O{sub 4} or FeO+Fe{sub 3}N nanoclusters), show that the ion irradiation behavior of nanocluster films such as these depends strongly on the initial nanostructure and chemistry.
- OSTI ID:
- 22117026
- Journal Information:
- AIP Conference Proceedings, Vol. 1525, Issue 1; Conference: 22. international conference on application of accelerators in research and industry, Ft. Worth, TX (United States), 5-10 Aug 2012; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
77 NANOSCIENCE AND NANOTECHNOLOGY
ANTIFERROMAGNETIC MATERIALS
ANTIFERROMAGNETISM
COERCIVE FORCE
HELIUM IONS
INTERFACES
ION MICROSCOPY
IRON
IRON NITRIDES
IRON OXIDES
IRRADIATION
MAGNETIC PROPERTIES
MAGNETIZATION
MEV RANGE
NANOSTRUCTURES
SILICON
SILICON IONS
TEMPERATURE RANGE 0273-0400 K
THIN FILMS
VIBRATING SAMPLE MAGNETOMETERS
X-RAY DIFFRACTION