Oxygen-deficient SrTiO sub 3 minus x , x = 0. 28, 0. 17, and 0. 08. Crystal growth, crystal structure, magnetic, and transport properties

Journal Article · Fri Feb 01 00:00:00 EST 1991 · Journal of Solid State Chemistry; (USA)

DOI:https://doi.org/10.1016/0022-4596(91)90149-C· OSTI ID:5624434

Gong, Wenhe; Yun, H; Ning, Y B; Greedan, J E; Datars, W R; Stager, C V ^[1]

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1. McMaster Univ., Hamilton, Ontario (Canada)

The grossly nonstoichiometric perovskites SrTiO{sub 3{minus}x} with x = 0.28, 0.17, and 0.08 were prepared from a reaction of Sr{sub 2}TiO{sub 4}, TiO, and TiO{sub 2} at 1,500{degree}C. For x = 0.28 relatively large single crystals were obtained. Also for this sample the crystal symmetry was found to depend on the rate of cooling from the reaction temperature and the annealing conditions. Rapidly cooled samples are tetragonal a = 3.9177(3) {angstrom}, c = 3.8878(5) {angstrom}. Samples annealed in vacuum at temperatures of 1,000 to 600{degree}C are cubic a = 3.9177(3) {angstrom}, c = 3.8878(5) {angstrom}. Samples annealed in vacuum at temperatures of 1,000 to 600{degree}C are cubic a = 3.9075(3) {angstrom} with no change in cell volume. Single crystal data from a tetragonal sample indicate slight preferential occupancy of one oxygen position in P4/mmm. No evidence for any supercell due to defect ordering could be seen by TEM in either cubic or tetragonal samples. The x = 0.28 crystals show metallic resistivity, {rho}(300 K) = 6 {times} 10{sup {minus}4} ohm-cm and temperature-independent paramagnetism. {chi}{sub m} = 118 {times} 10{sup {minus}6} cm{sup 3} mole{sup {minus}1}. Hall effect data from 300 to 4.2 K analyzed on a single carrier model give a temperature-independent n-type carrier density of 2.4 {times} 10{sup 21} cm{sup {minus}3}.

• OSTI ID: 5624434
• Journal Information: Journal of Solid State Chemistry; (USA), Vol. 90:2; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
STRONTIUM OXIDES
CRYSTAL GROWTH
CRYSTAL STRUCTURE
HALL EFFECT
TITANIUM OXIDES
EXPERIMENTAL DATA
LATTICE PARAMETERS
MONOCRYSTALS
PEROVSKITES
TEMPERATURE DEPENDENCE
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
CRYSTALS
DATA
DIFFRACTION
ELECTRON MICROSCOPY
INFORMATION
MICROSCOPY
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
SCATTERING
STRONTIUM COMPOUNDS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360201* - Ceramics
Cermets
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360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360204 - Ceramics
Cermets
& Refractories- Physical Properties