Effect of oxygen stoichiometry on the electrical properties of La{sub 0.5}Sr{sub 0.5}CoO{sub 3} electrodes

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.364991· OSTI ID:496400

Madhukar, S; Aggarwal, S; Dhote, A M; Ramesh, R ^[1]; Krishnan, A ^[2]; Keeble, D ^[3]; Poindexter, E ^[4]

---

1. Department of Materials and Nuclear Engineering, University of Maryland, College Park, Maryland 20742 (United States)
2. Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States)
3. Carnegie Laboratory of Physics, University of Dundee, Dundee DD14HN (United Kingdom)
4. Army Research Laboratory, Fort Monmouth, New Jersey 07703 (United States)

We report on the metal-insulator transition of La{sub 0.5}Sr{sub 0.5}CoO{sub 3} thin films deposited by pulsed laser ablation on LaAlO{sub 3} substrates. The films were cooled in oxygen partial pressures between 760 and 10{sup {minus}5} Torr and electrical resistivity of the films was measured as a function of cooling oxygen pressure. La{sub 0.5}Sr{sub 0.5}CoO{sub 3} films changed from metallic to insulating behavior depending on their oxygen content. A defect model has been proposed to explain this transition and the change in conductivity is related to the change in the oxidation state of the cobalt ions. The model explains the relationship between oxygen partial pressure and electrical conductivity in La{sub 0.5}Sr{sub 0.5}CoO{sub 3}, which describes the experimental dependence reasonably well. Positron annihilation studies were also done on the same set of samples and the S parameter was seen to increase by 8{percent} from a fully oxygenated sample to a sample cooled in 10{sup {minus}5} Torr. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 496400
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 81; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COBALT OXIDES
ELECTRIC CONDUCTIVITY
ELECTRODES
EPITAXY
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
OXYGEN
PARTIAL PRESSURE
POSITRONS
SEMICONDUCTOR MATERIALS
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
THIN FILMS