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X-ray photoemission electron microscope determination of origins of room temperature ferromagnetism and photoluminescence in high co-content coxzn1-xo films.

Cao, Wei; Pankratov, Vladimir; Huttula, Marko; Shirmane, Liana; Niu, Yuran LU and Wang, Feng (2014) In Surface Review and Letters 21(4).
Abstract
In this paper, we reported on the X-ray photoemission electron microscope (XPEEM) determination of magnetic and luminescence origins for two CoxZn1-xO films. The cobalt fraction x of radio frequency co-sputtered samples were 0.86(2) and 0.92(2), respectively. Films were ferromagnetic and semiconductive. Unique narrow green color lines beside the ZnO intrinsic emissions were found with a decay time in microsecond range at room temperature. Origins of magnetic and luminescence properties were determined with XPEEM. The X-ray absorption near edge structure at the CoL3-edge denoted that Co was partially oxidized, and phase-contrast images together with chemical composition identification further proved that Co and CoO co-existed in the... (More)
In this paper, we reported on the X-ray photoemission electron microscope (XPEEM) determination of magnetic and luminescence origins for two CoxZn1-xO films. The cobalt fraction x of radio frequency co-sputtered samples were 0.86(2) and 0.92(2), respectively. Films were ferromagnetic and semiconductive. Unique narrow green color lines beside the ZnO intrinsic emissions were found with a decay time in microsecond range at room temperature. Origins of magnetic and luminescence properties were determined with XPEEM. The X-ray absorption near edge structure at the CoL3-edge denoted that Co was partially oxidized, and phase-contrast images together with chemical composition identification further proved that Co and CoO co-existed in the samples. The ferromagnetism was attributed to ferromagnetism of Co clusters partially canceled by the antiferromagnetism of its oxide, and the photoluminescence to bound exciton in ZnO nanoclusters and defect related centers of ZnO nanoclusters in a Co-rich matrix. Present results show possibilities for adjusting magnetic and luminescence properties of Co-ZnO compounds by changing the cobalt concentration. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Co-concentrated Co-ZnO films, photoluminescence, magnetism, synchrotron, radiation, photoemission electron microscope
in
Surface Review and Letters
volume
21
issue
4
publisher
World Scientific
external identifiers
  • wos:000340610900016
  • scopus:84906101486
ISSN
0218-625X
DOI
10.1142/S0218625X14500589
language
English
LU publication?
yes
id
5e440ad8-b030-44d0-80ee-f9a2720f2edf (old id 4659321)
date added to LUP
2014-09-24 15:14:17
date last changed
2017-01-01 05:50:31
@article{5e440ad8-b030-44d0-80ee-f9a2720f2edf,
  abstract     = {In this paper, we reported on the X-ray photoemission electron microscope (XPEEM) determination of magnetic and luminescence origins for two CoxZn1-xO films. The cobalt fraction x of radio frequency co-sputtered samples were 0.86(2) and 0.92(2), respectively. Films were ferromagnetic and semiconductive. Unique narrow green color lines beside the ZnO intrinsic emissions were found with a decay time in microsecond range at room temperature. Origins of magnetic and luminescence properties were determined with XPEEM. The X-ray absorption near edge structure at the CoL3-edge denoted that Co was partially oxidized, and phase-contrast images together with chemical composition identification further proved that Co and CoO co-existed in the samples. The ferromagnetism was attributed to ferromagnetism of Co clusters partially canceled by the antiferromagnetism of its oxide, and the photoluminescence to bound exciton in ZnO nanoclusters and defect related centers of ZnO nanoclusters in a Co-rich matrix. Present results show possibilities for adjusting magnetic and luminescence properties of Co-ZnO compounds by changing the cobalt concentration.},
  articleno    = {1450058},
  author       = {Cao, Wei and Pankratov, Vladimir and Huttula, Marko and Shirmane, Liana and Niu, Yuran and Wang, Feng},
  issn         = {0218-625X},
  keyword      = {Co-concentrated Co-ZnO films,photoluminescence,magnetism,synchrotron,radiation,photoemission electron microscope},
  language     = {eng},
  number       = {4},
  publisher    = {World Scientific},
  series       = {Surface Review and Letters},
  title        = {X-ray photoemission electron microscope determination of origins of room temperature ferromagnetism and photoluminescence in high co-content coxzn1-xo films.},
  url          = {http://dx.doi.org/10.1142/S0218625X14500589},
  volume       = {21},
  year         = {2014},
}