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Insight into the Growth Reaction Mechanism of Ceramic Co 3 TeO 6 : Synchrotron Structural and Thermal Analysis
Author(s) -
Singh Harishchandra,
Sinha Anil K.,
Gupta Surya M.,
Singh Manvendra N.,
Ghosh Haranath
Publication year - 2016
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/jace.14357
Subject(s) - monoclinic crystal system , rietveld refinement , multiferroics , valence (chemistry) , materials science , solid state reaction route , crystallography , xanes , cobalt , ceramic , extended x ray absorption fine structure , crystal structure , chemistry , inorganic chemistry , absorption spectroscopy , ferroelectricity , physics , optoelectronics , organic chemistry , quantum mechanics , spectroscopy , dielectric , composite material
A two‐step solid‐state reaction is proposed to synthesize monophasic cobalt tellurate Co 3 TeO 6 ( CTO ), a type II multiferroic, using Co 3 O 4 and TeO 2 as the starting reagents. First step of the reaction results in the secondary monoclinic ( P 2 1 / c ) CoTeO 4 compound, which on further calcination (second step) leads to the primary monoclinic ( C 2/ c ) Co 3 TeO 6 phase. High‐resolution synchrotron X‐ray diffraction and the subsequent Rietveld analysis are used to probe different phases present in the synthesized CTO and to achieve its single phase. X‐ray absorption near‐edge structure studies at Co K and Te L edges reveal mixed oxidation states (Co 2+/3+ ) of Co and hexavalent Te, respectively. Charge imbalance due to mixed valence Co ions has been attributed to cations vacancies. Enhanced multiferroic properties, such as effective magnetic moment, spin phonon coupling, etc., have been attributed to the aforementioned observations in grown ceramic CTO via proposed synthesis route.