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Title:
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Structure and magnetic properties of Co-doped ZnO nanoparticles
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Author:
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Martínez Benjamin, Joan Josep; Sandiumenge Ortiz, Felip; Balcells i Argemí, Lluís; Arbiol i Cobos, Jordi; Sibieude, F.; Monty, C.
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Other authors:
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Universitat de Barcelona |
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Abstract:
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In this work we carefully analyze the role of the microstructure on the magnetic properties of Co-doped ZnO
nanoparticles prepared by the vaporization-condensation method in a solar reactor. We show that a close
correlation exists between microstructural features and the appearance of ferromagnetism. Both shape and size
of the particles, as well as the microstructure, can be controlled by changing the pressure inside the evaporation
chamber, as evidenced by transmission electron microscopy micrographs and high resolution electron microscopy
HREM. X-ray diffraction patterns and HREM make evident the absence of any significant Co segregation
or any other phase different from würtzite type ZnO. On the other hand, electron energy loss spectroscopy
analyses performed on several particles of würtzite type ZnO yielded an average Co concentration in
good agreement with the nominal composition. Samples prepared in low pressure 10 Torr exhibit a very
homogeneous microstructure and are ferromagnetic at low temperature but they have a very small saturation
moment, well below that expected for a Co2+ ion. Conversely, samples prepared at higher pressure conditions
70–100 Torr show a defective microstructure and are paramagnetic and increasing the Co content does not
induce ferromagnetism. |
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Subject(s):
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-Nanopartícules
-Propietats magnètiques
-Magnetic properties and materials |
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Rights:
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(c) The American Physical Society, 2005
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Document type:
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Article
Article - Published version |
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Published by:
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The American Physical Society
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