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Title: Dopant spin states and magnetism of Sn{sub 1−x}Fe{sub x}O{sub 2} nanoparticles

This work reports detailed investigations of a series of ∼2.6 nm sized, Sn{sub 1−x}Fe{sub x}O{sub 2} crystallites with x = 0–0.10 using Mossbauer spectroscopy, x-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance spectroscopy (EPR), and magnetometry to determine the oxidation state of Fe dopants and their role in the observed magnetic properties. The magnetic moment per Fe ion μ was the largest ∼6.48 × 10{sup −3} μ{sub B} for the sample with the lowest (0.001%) Fe doping, and it showed a rapid downward trend with increasing Fe doping. Majority of the Fe ions are in 3+ oxidation state occupying octahedral sites. Another significant fraction of Fe dopant ions is in 4+ oxidation state and a still smaller fraction might be existing as Fe{sup 2+} ions, both occupying distorted sites, presumably in the surface regions of the nanocrystals, near oxygen vacancies. These studies also suggest that the observed magnetism is not due to exchange coupling between Fe{sup 3+} spins. A more probable role for the multi-valent Fe ions may be to act as charge reservoirs, leading to charge transfer ferromagnetism.
Authors:
; ; ; ; ;  [1] ;  [1] ;  [2] ;  [3]
  1. Department of Physics, Boise State University, Boise, Idaho 83725-1570 (United States)
  2. (Colombia)
  3. Grupo de Estado Sólido, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No 52-21, Medellín (Colombia)
Publication Date:
OSTI Identifier:
22273708
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; DOPED MATERIALS; ELECTRON SPIN RESONANCE; FERROMAGNETISM; IRON COMPOUNDS; IRON IONS; MAGNETIC MOMENTS; MAGNETIC PROPERTIES; MOESSBAUER EFFECT; NANOSTRUCTURES; OXYGEN; PARTICLES; SPIN; TIN OXIDES; VACANCIES; VALENCE; X-RAY PHOTOELECTRON SPECTROSCOPY