Synthesis of Metastable, Wurzite‐Based Zinc Oxide‐Cobalt(II) Oxide Solid Solutions by Spray Pyrolysis

Jayaram, Vikram; Rajkumar, Johanna; Rani, Bindu

doi:10.1111/j.1551-2916.1999.tb20090.x

Cited by 25 publications

(20 citation statements)

References 15 publications

(20 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…26 Most of the experimental results show that, among transition-metal dopants, Co-doped ZnO systems are ferromagnetic in both thin films as well as bulk materials. 13,16,27 Also, there have been few reports of ferromagnetism in Mn-, 28,29 Ni-, 30 and some other TM-doped 31 ͑such as Cr or V͒ ZnO. The ferromagnetism in the Mn-doped system is yet to be understood, as Mn in the +2 valence state does not dope any carrier into the ZnO system and hence, by first-principles studies, 24 must lead to an antiferromagnetic ground state.…”

Section: Introductionmentioning

confidence: 99%

Ferromagnetism in Fe-doped ZnO nanocrystals: Experiment and theory

et al. 2007

View full text Add to dashboard Cite

Fe-doped ZnO nanocrystals are successfully synthesized and structurally characterized by using x-ray diffraction and transmission electron microscopy. Magnetization measurements on the same system reveal a ferromagnetic to paramagnetic transition temperature above 450 K with a low-temperature transition from the ferromagnetic to the spin-glass state due to canting of the disordered surface spins in the nanoparticle system. Local magnetic probes like electron paramagnetic resonance and Mössbauer spectroscopy indicate the presence of Fe in both valence states Fe 2+ and Fe 3+ . We argue that the presence of Fe 3+ is due to possible hole doping in the system by cation ͑Zn͒ vacancies. In a subsequent ab initio electronic structure calculation, the effects of defects ͑e.g., O and Zn vacancies͒ on the nature and origin of ferromagnetism are investigated for the Fe-doped ZnO system. Electronic structure calculations suggest hole doping ͑Zn vacancy͒ to be more effective to stabilize ferromagnetism in Fe-doped ZnO and our results are consistent with the experimental signature of hole doping in ferromagnetic Fe-doped ZnO samples.

show abstract

Section: Introductionmentioning

confidence: 99%

Ferromagnetism in Fe-doped ZnO nanocrystals: Experiment and theory

et al. 2007

View full text Add to dashboard Cite

show abstract

“…on the partial solubility of cobalt in zinc oxide and zinc in the different cobalt oxides. This topic has been also analyzed in the literature and different interesting data have been obtained working with hydrothermal techniques, 22) diffusion couples, 23) hydrolysis reactions in polyol medium, 24) spray pyrolysis, 25) freeze-drying, 26) or even dip coating. 27) With all these data in mind, the present contribution faces the analysis of the thermal evolution of the ZnCo 2 O 4 nominal phase in order to throw some light on the stability of a ceramic material which is finding application in current technologies.…”

Section: Introductionmentioning

confidence: 99%

Thermal evolution of ZnCo2O4 spinel phase in air

Peiteado

Caballero

Makovec

2010

J. Ceram. Soc. Japan

View full text Add to dashboard Cite

ZnCo 2 O 4 ceramics with a spinel-like structure are versatile functional materials which depending on the synthesis conditions may exhibit magnetic, electric, optical and/or catalytic characteristics. However under air atmosphere, cobalt ions experiment different red-ox processes with temperature, so contrary to many other spinel oxides, a low thermal stability can be expected for this cobaltite spinels. In addition, the final outcome of these transformations will be as well defined by the solid state chemistry of the ZnOCo x O y couple, i.e. by the partial solubility of cobalt in zinc oxide and zinc in the different cobalt oxides. At first the similarity in charge and ionic size suggests the possibility of substitutional solid solution for both the Co II into the ZnO wurtzite structure and the Zn II into the CoO rock-salt structure. However it has been observed that once the spinel structure collapses, all the zinc diffuses into the rock salt phase.

show abstract

“…ZnO is one of the best candidates; it is optically transparent and has n or p type conductivity depending on the doping or co-doping technique [3]. Many studies were done on Co:ZnO films which were deposited either by pulsed laser deposition (PLD) using a KrF laser [4], a sol-gel method [5], radio-frequency magnetron co-sputtering [6], or spray pyrolysis [7]. In this work a study of structural and optical properties of undoped and Co doped ZnO films grown onto borosilicate glass substrates, using aerosol assisted chemical vapour deposition method.…”

Section: Introductionmentioning

confidence: 99%