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Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/10054/4747

Title: Ferromagnetism in Fe-doped ZnO nanocrystals: Experiment and theory
Authors: KARMAKAR, D
MANDAL, SK
KADAM, RM
PAULOSE, PL
RAJARAJAN, AK
NATH, TK
DAS, AK
DASGUPTA, I
DAS, GP
Keywords: diluted magnetic semiconductor
room-temperature ferromagnetism
spin-glass behavior
zinc ferrite
thin-films
mn
nanoparticles
exchange
bulk
transport
Issue Date: 2007
Publisher: AMERICAN PHYSICAL SOC
Citation: PHYSICAL REVIEW B, 75(14), -
Abstract: Fe-doped ZnO nanocrystals are successfully synthesized and structurally characterized by using x-ray diffraction and transmission electron microscopy. Magnetization measurements on the same system reveal a ferromagnetic to paramagnetic transition temperature above 450 K with a low-temperature transition from the ferromagnetic to the spin-glass state due to canting of the disordered surface spins in the nanoparticle system. Local magnetic probes like electron paramagnetic resonance and Mossbauer spectroscopy indicate the presence of Fe in both valence states Fe2+ and Fe3+. We argue that the presence of Fe3+ is due to possible hole doping in the system by cation (Zn) vacancies. In a subsequent ab initio electronic structure calculation, the effects of defects (e.g., O and Zn vacancies) on the nature and origin of ferromagnetism are investigated for the Fe-doped ZnO system. Electronic structure calculations suggest hole doping (Zn vacancy) to be more effective to stabilize ferromagnetism in Fe-doped ZnO and our results are consistent with the experimental signature of hole doping in ferromagnetic Fe-doped ZnO samples.
URI: http://dx.doi.org/10.1103/PhysRevB.75.144404
http://dspace.library.iitb.ac.in/xmlui/handle/10054/4747
http://hdl.handle.net/10054/4747
ISSN: 1098-0121
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