Vacancy related defects in La{sub 0.5}Sr{sub 0.5}CoO{sub 3-{delta}} thin films

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:475599

Keeble, D J ^[1]; Krishnan, A ^[2]; Nielsen, B ^[3]

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1. Univ. of Dundee (United Kingdom). Carnegie Lab. of Physics
2. Michigan Technological Univ., Houghton, MI (United States). Dept. of Physics
3. Brookhaven National Lab., Upton, NY (United States); and others

Laser ablated La{sub 0.5}Sr{sub 0.5}CoO{sub 3-{delta}} thin films have been studied by Doppler-broadening-detected positron annihilation using a variable-energy positron beam. The oxygen partial pressure during cooling from the growth temperature was altered through the range 760 torr to 10{sup -5} torr to change the oxygen non-stoichiometry of the films. The measured Doppler broadened lineshape parameter S was found to increase with increasing oxygen nonstoichiometry. For films cooled with an oxygen partial pressure of {le} 10{sup -4} Torr positron trapping to monovacancy type defects is inferred. For the film cooled in 10{sup -5} torr oxygen the magnitude of the increase in S, with respect to that measured from the film cooled in 760 Torr oxygen, showed positron trapping to vacancy cluster defects was occurring.

• Research Organization: Brookhaven National Lab., Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: AA03-78CH00017
• OSTI ID: 475599
• Report Number(s): BNL--64278; CONF-961202--109; ON: DE97006100
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COBALT OXIDES
DOPPLER BROADENING
LANTHANUM OXIDES
PEROVSKITES
STRONTIUM OXIDES
THIN FILMS
VACANCIES