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Influence of Nanocrystallization on the Electronic Conductivity of Zinc Iron Phosphate Glass
Author(s) -
MogušMilanković Andrea,
Sklepić Kristina,
Skoko Željko,
Mikac Lara,
Musić Svetozar,
Day Delbert E.
Publication year - 2012
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2011.04781.x
Subject(s) - materials science , crystallite , crystallization , electrical resistivity and conductivity , polaron , conductivity , phase (matter) , analytical chemistry (journal) , dielectric spectroscopy , thermal conduction , mineralogy , chemical engineering , metallurgy , composite material , chemistry , electron , electrode , physics , electrical engineering , organic chemistry , chromatography , quantum mechanics , engineering , electrochemistry
The effect of nanocrystallization on the electronic conductivity of 10 ZnO –30 Fe 2 O 3 –60 P 2 O 5 glass has been investigated using differential thermal analysis ( DTA ), XRD , R aman, and impedance spectroscopy. The structural evolution of glass during heat treatment at various temperatures for 24 h is characterized by the dendrite‐like phase separation in the early stage of nanocrystallization, which produces isolated agglomerates of Fe 3 ( P 2 O 7 ) 2 crystallites. Formation of randomly dispersed agglomerates of Fe 3 ( P 2 O 7 ) 2 crystalline grains results in a decrease of Fe 2+ – Fe 3+ pairs concentration in a predominant glassy phase causing a minimum in electrical conductivity at 8.82 × 10 −13 (Ω·cm) −1 . With increasing the heating temperature up to the first crystallization temperature, T C1 , the conductivity increases and simultaneously the activation energy decreases as the nanocrystallization is more pronounced in these samples. Heat treatment at higher temperature near T C2 exhibits the highest electrical conductivity, 2.97 × 10 −10 (Ω·cm) −1 . Upon heating at T C2 , the sample undergoes further nanocrystallization causing slight decrease in the electrical conductivity. This effect can be understood as a result of the partial blocking of conduction pathways for the polarons along the interfaces between polycrystalline grains and through poorly conductive crystallites. The conductivity of this thermally treated glass is independent of the ZnO content and arises from the polaron hopping between Fe 2+ and Fe 3+ ions suggesting electronic conduction.