Oxygen exchange kinetics of epitaxial PrBaCo2O5+δ thin films

Abstract

The oxygen exchange kinetics of thin films of the oxygen-deficient double perovskite PrBaCo2O5+δ (PBCO) have been determined by electrical conductivity relaxation (ECR) and by oxygen-isotope exchange and depth profiling (IEDP). Microstructural studies indicate that the PBCO films, prepared by pulsed laser deposition, have excellent single-crystal quality and epitaxial nature. The ECR and IEDP measurements reveal that the PBCO films have high electronic conductivity and rapid surface exchange kinetics, although the ECR data indicate the presence of two distinct kinetic pathways. The rapid surface kinetics compared with those of other perovskites suggest the application of PBCO as a cathode material in intermediate-temperature solid oxide fuel cells.

PO 2 dependant resistance switch effect in highly epitaxial (LaBa)Co2O5+δ thin films

“…[3][4][5] In this family of compounds, the A-site cationic ordered arrangement is favored due to the large difference in Ba 2+ and rare earth ionic radii, except ͑LaBa͒Co 2 O 5+␦ ͑LBCO͒. In LBCO, the doped bivalent Ba 2+ is not only inducing plenty of oxygen deficiency but also structurally providing the capability to achieve the smallest oxygen deficiency in this family of compounds due to the very similar ionic radii between Ba 2+ and La 3+ .…”

Epitaxial behavior and transport properties of PrBaCo2O5 thin films on (001) SrTiO3

“…The low temperature structural properties of these compounds have been studied in detail [4][5][6][7][8] and some data are available on their high temperature oxygen chemistry. [9][10][11][12] Recently, Streule et al 8 have measured high rates of oxygen uptake in GdBaB 2 O 5+x ͑B=Mn,Co͒ together with clear indications that the ordered vacancies are important to this process. We have also observed facile oxygen uptake in PrBaCo 2 O 5+x ͑PBCO͒ powders and determined the oxygen diffusion and surface exchange rates.…”

“…10 Similar rapid surface exchange kinetics were observed on thin films of PBCO prepared by pulsed laser deposition. 11 In this letter, we report the low temperature transport phenomena and magnetic properties of the highly epitaxial PBCO thin films on single crystal ͑001͒ SrTiO 3 ͑STO͒ substrates. Two types of domains and spinglass interaction behavior in magnetoresistance studies were found in the highly epitaxial PBCO thin films.…”

“…Both PBCO ͑200͒ and ͑004͒ peaks were observed, indicating that the as-grown PBCO films are a axis oriented with two different domain structures in the directions parallel to the substrate surface. 11 The crystallinity and epitaxial quality of the as-grown films were further investigated by TEM. A dark field cross sectional TEM image ͓Fig.…”

“…An energy density of about 2.0 J / cm 2 and a laser repetition rate of 5 Hz were adopted during film deposition. A single phase PBCO target prepared for the film deposition, as described previously, 11 was used. Single-crystal ͑001͒ STO ͑c STO = 3.905 Å͒ was selected as the substrate for epitaxial growth of PBCO thin films due to the good lattice match, about −2.2%, estimated from the standard crystal lattice parameters of PBCO ͑c PBCO = 7.6343 Å͒ and STO.…”