Synthesis and electrical conductivity of perovskite-type PrCo 1-xMg xO 3

Document Type

Article

Publication Date

11-1-2004

Abstract

Oxides in the system PrCo 1-xMg xO 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-Pm3m). The maximum ratio of doped Mg in the system PrCo 1 -xMg xO 3 is x=0.2. Further doping leads to the segregation of Pr 6O 11 in PrCo 1 -xMg xO 3. The substitution of Mg for Co improves the performance of PrCoO 3 as compared to the electrical conductivity measured by a four-probe electrical conductivity analyzer in the temperature range from 298 to 1073 K. The substitution of Mg for Co on the B site may be compensated by the formations of Co 4+ and oxygen vacancies. The electrical conductivity of PrCo 1-xMg xO 3 oxides increases with increasing x in the range of 0.0-0.2. The increase in conductivity becomes considerable at the temperatures ≥673 K especially for x≥0.1; it reaches a maximum at x=0.2 and 1073 K. From x>0.2 the conductivity of PrCo 1-xMg xO 3 starts getting lower. This is probably a result of the segregation of Pr 6O 11 in PrCo 1-xMg xO 3, which blocks oxygen transport, and association of oxygen vacancies. A change in activation energy for all PrCo 1 -xMg xO 3 compounds (x=0-0.25) was observed, with a higher activation energy above 573 K and a lower activation energy below 573 K. The reasons for such a change are probably due to the change of dominant charge carriers from Co 4+ to Vö in PrCo 1 -xMg xO 3 oxides and a phase transition mainly starting at 573 K. © 2004 Elsevier Inc. All rights reserved.

Identifier

9144247031 (Scopus)

Publication Title

Journal of Solid State Chemistry

External Full Text Location

https://doi.org/10.1016/j.jssc.2004.07.023

ISSN

00224596

First Page

3977

Last Page

3980

Issue

11

Volume

177

Grant

20031020

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