Synthesis and electrical conductivity of perovskite-type PrCo{sub 1-x}Mg{sub x}O{sub 3}

Journal Article · Mon Nov 01 00:00:00 EST 2004 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2004.07.023· OSTI ID:20658176

Yinzhe, Ren ^[1]; Baoan, Li ^[1]; Jianying, Wang ^[1]; Xiaohong, Xu ^[1]

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1. School of Chemistry and Materials Science, Shanxi Normal University, Linfen 041004 (China)

Oxides in the system PrCo{sub 1-x}Mg{sub x}O{sub 3} (x=0.0, 0.05, 0.10, 0.15, 0.20, 0.25) were synthesized by citrate technique and characterized by powder X-ray diffraction and scanning electron microscope. All compounds have a cubic perovskite structure (space group Oh1-Pm3-bar m). The maximum ratio of doped Mg in the system PrCo{sub 1-x}Mg{sub x}O{sub 3} is x=0.2. Further doping leads to the segregation of Pr{sub 6}O{sub 11} in PrCo{sub 1-x}Mg{sub x}O{sub 3}. The substitution of Mg for Co improves the performance of PrCoO{sub 3} as compared to the electrical conductivity measured by a four-probe electrical conductivity analyzer in the temperature range from 298 to 1073K. The substitution of Mg for Co on the B site may be compensated by the formations of Co{sup 4+} and oxygen vacancies. The electrical conductivity of PrCo{sub 1-x}Mg{sub x}O{sub 3} oxides increases with increasing x in the range of 0.0-0.2. The increase in conductivity becomes considerable at the temperatures >=673K especially for x>=0.1; it reaches a maximum at x=0.2 and 1073K. From x>0.2 the conductivity of PrCo{sub 1-x}Mg{sub x}O{sub 3} starts getting lower. This is probably a result of the segregation of Pr{sub 6}O{sub 11} in PrCo{sub 1-x}Mg{sub x}O{sub 3} , which blocks oxygen transport, and association of oxygen vacancies. A change in activation energy for all PrCo{sub 1-x}Mg{sub x}O{sub 3} compounds (x=0-0.25) was observed, with a higher activation energy above 573K and a lower activation energy below 573K. The reasons for such a change are probably due to the change of dominant charge carriers from Co{sup 4+} to Vo in PrCo{sub 1-x}Mg{sub x}O{sub 3} oxides and a phase transition mainly starting at 573K.

• OSTI ID: 20658176
• Journal Information: Journal of Solid State Chemistry, Vol. 177, Issue 11; Other Information: DOI: 10.1016/j.jssc.2004.07.023; PII: S0022-4596(04)00409-8; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COBALT COMPOUNDS
CUBIC LATTICES
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
MAGNESIUM COMPOUNDS
OXIDES
PEROVSKITE
PRASEODYMIUM COMPOUNDS
SCANNING ELECTRON MICROSCOPY
SEGREGATION
SPACE GROUPS
X-RAY DIFFRACTION