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Title: Magnetic properties of nanocrystalline KNbO{sub 3}

Newly synthesized undoped and iron-doped nanoscale powders of KNbO{sub 3} are investigated using magnetic resonance and static magnetization methods in order to determine how the crystal size and doping affect the structure of magnetic defects and material properties. Although the bulk crystals of KNbO{sub 3} are nonmagnetic, the undoped KNbO{sub 3} powder with average particle size of 80 nm exhibits magnetic properties. The ferromagnetic resonance signal and the magnetization curve registered on the powder are thoroughly analyzed. It is concluded that the appearance of the defect driven ferromagnetism in the undoped powder is due to the nano-size of the particles. This effect disappears in the iron-doped KNbO{sub 3} powder with particle sizes above 300 nm. In case of low doping (<1 mol. % Fe), a new electron paramagnetic resonance signal with g{sub eff} = 4.21 is found out in the KNbO{sub 3}:Fe powder. Such a signal has not been observed in the bulk crystals of KNbO{sub 3}:Fe. We suppose that this signal corresponds to individual paramagnetic Fe{sup 3+} ions having rhombic symmetry.
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Institute of Semiconductor Physics of NAS of Ukraine, Pr. Nauky 41, 03028 Kyiv (Ukraine)
  2. Quality Engineering Education, Inc., Buffalo Grove, Illinois 60089 (United States)
  3. National Technical University of Ukraine “KPI”, pr. Peremogy 37, 03056 Kyiv (Ukraine)
Publication Date:
OSTI Identifier:
22257800
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 17; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CRYSTALS; DEFECTS; DOPED MATERIALS; ELECTRON SPIN RESONANCE; FERROMAGNETIC RESONANCE; FERROMAGNETISM; IRON IONS; MAGNETIC PROPERTIES; MAGNETIZATION; NANOSTRUCTURES; NIOBATES; PARAMAGNETISM; PARTICLE SIZE; POWDERS