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|title: ||Surface modification of Co-doped ZnO nanocrystals and its effects on the magnetic properties|
|authors: ||Pereira, A. S.|
Ankiewicz, A. O.
Carmo, M. C.
Sobolev, N. A.
|issue date: ||2008|
|publisher: ||American Institute of Physics|
|abstract: ||A series of chemically prepared Co2+-doped ZnO colloids has been surface modified either by
growing shells of ZnSe or by the in situ encapsulation in poly styrene . The surface modification
effects using these two distinct chemical strategies on the magnetic properties of the nanocrystals
were probed by electron paramagnetic resonance EPR . Structural characterization by means of
x-ray diffraction and transmission electron microscopy gave no evidence of second phase formation
within the detection limits of the used equipment. The EPR analysis was carried out by simulations
of the powderlike EPR spectra. The results confirm that in the core of these nanocrystals Co was
incorporated as Co2+, occupying the Zn2+ sites in the wurtzite structure of ZnO. Additionally we
identify two Co signals stemming from the nanocrystals’ shell. The performed surface modifications
clearly change the relative intensity of the EPR spectrum components, revealing the core and shell
|publisher version/DOI: ||dx.doi.org/10.1063/1.2833300|
|source: ||Journal Of Applied Physics|
|appears in collections||DQ - Artigos|
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