TY - JOUR
T1 - A structure, conductivity and dielectric properties investigation of A 3CoNb 2O 9 (A=Ca 2+, Sr 2+, Ba 2+) triple perovskites
AU - Ting, V.
AU - Liu, Y.
AU - Norén, L.
AU - Withers, R. L.
AU - Goossens, D. J.
AU - James, M.
AU - Ferraris, C.
PY - 2004/12
Y1 - 2004/12
N2 - The room temperature structures as well as the temperature-dependent conductivity and dielectric properties of the A 3CoNb 2O 9 (A=Ca 2+, Sr 2+ and Ba 2+) triple perovskites have been carefully investigated. A constrained modulation wave approach to Rietveld structure refinement is used to determine their room temperature crystal structures. Correlations between these crystal structures and their physical properties are found. All three compounds undergo insulator to semiconductor phase transitions as a function of increasing temperature. The hexagonal Ba 3CoNb 2O 9 compound acts as an insulator at room temperature, while the monoclinic Ca 3CoNb 2O 9 compound is already a semiconductor at room temperature. The measured dielectric frequency characteristics of the A=Ba compound are excellent. Measured temperature dependence of the electrical resistivity of the three A 3CoNb 2O 9, A=Ca, Sr and Ba, complex perovskite samples.
AB - The room temperature structures as well as the temperature-dependent conductivity and dielectric properties of the A 3CoNb 2O 9 (A=Ca 2+, Sr 2+ and Ba 2+) triple perovskites have been carefully investigated. A constrained modulation wave approach to Rietveld structure refinement is used to determine their room temperature crystal structures. Correlations between these crystal structures and their physical properties are found. All three compounds undergo insulator to semiconductor phase transitions as a function of increasing temperature. The hexagonal Ba 3CoNb 2O 9 compound acts as an insulator at room temperature, while the monoclinic Ca 3CoNb 2O 9 compound is already a semiconductor at room temperature. The measured dielectric frequency characteristics of the A=Ba compound are excellent. Measured temperature dependence of the electrical resistivity of the three A 3CoNb 2O 9, A=Ca, Sr and Ba, complex perovskite samples.
KW - A CoNb O complex perovskites
KW - Dielectric properties
KW - Resistivity insulator to semiconductor phase transitions
KW - Rietveld refinement
UR - http://www.scopus.com/inward/record.url?scp=10644280996&partnerID=8YFLogxK
U2 - 10.1016/j.jssc.2004.09.016
DO - 10.1016/j.jssc.2004.09.016
M3 - Article
SN - 0022-4596
VL - 177
SP - 4428
EP - 4442
JO - Journal of Solid State Chemistry
JF - Journal of Solid State Chemistry
IS - 12
ER -