The crystal chemistry and physical properties of the triple layer perovskite intergrowths LaSr[sub 3]Fe[sub 3]O[sub 10[minus][delta]] and LaSr[sub 3](Fe[sub 3[minus]x]Al[sub x])O[sub 10[minus][delta]]

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1072· OSTI ID:6351977

Lee, J Y; Swinnea, J S; Steinfink, H ^[1]; Reiff, W M ^[2]; Pei, S; Jorgensen, J D ^[3]

---

1. Univ. of Texas, Austin (United States)
2. Northeastern Univ., Boston, MA (United States)
3. Argonne National Lab., IL (United States)

Single-crystal X-ray diffraction and neutron powder diffraction analyses were employed to study the reversible intercalation of oxygen in the phase LaSr[sub 3]Fe[sub 3]O[sup 10[minus][delta]] and in the mixed Fe/Al analogue. A single-crystal X-ray diffraction study was done on LaSr[sub 3](Fe[sub 0.8]Al[sub 0.2])[sub 3]O[sub 8.95]. The crystal structure consists of a triple layer of octahedra separated by La/Sr-O layers. The oxygen stoichiometry is variable and Rietveld refinement of neutron powder diffraction data in addition to the X-ray study was used to determine the vacancy sites. The vacancies occur primarily in the equatorial layer of the central octahedron. The value of the c-axis parameter is a linear function of the oxygen stoichiometry and increases with decreasing oxygen content. The range of the c-axis variation is narrower for the Al-containing phase than for the pure Fe compounds. Intercalation of oxygen occurs reversibly as a function of temperature. A given oxygen stoichiometry can be obtained by quenching the material from an elevated temperature into liquid nitrogen. The thermal displacement parameter of the cation occupying the central octahedron increases in the (001) plane with increasing oxygen deficiency in the equatorial layer of this octahedron. This displacement is interpreted as motion of the cation into a tetrahedral coordination environment. The range of oxygen stoichiometry for LaSr[sub 3]Fe[sub 3]O[sub 10[minus][delta]] is 0.1 [le] [delta] [le] 0.8; for the Al-containing phase it is 0.65 [le] [delta] [le] 1.1. Single-phase material can be synthesized with La, Nd, Pr, and Gd but not with Er. No substitution of Sr by Ba or Ca was possible. The solid solution range Sr[sub 4[minus]x]La[sub x] is very narrow, 0.96 [le] x [le] 1.04. 26 refs., 8 figs., 6 tabs.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6351977
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 103:1; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATIONS
CHALCOGENIDES
CHARGED PARTICLES
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFRACTION
DISPERSIONS
ERBIUM COMPOUNDS
ERBIUM OXIDES
EXCHANGE INTERACTIONS
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
INTERACTIONS
IONS
IRON COMPOUNDS
IRON OXIDES
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
LAYERS
MILLER INDICES
MINERALS
MIXTURES
NEODYMIUM COMPOUNDS
NEODYMIUM OXIDES
NEUTRON DIFFRACTION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PEROVSKITE
PEROVSKITES
PHYSICAL PROPERTIES
POINT DEFECTS
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
QUENCHING
RARE EARTH COMPOUNDS
SCATTERING
SOLID SOLUTIONS
SOLUTIONS
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TRANSITION ELEMENT COMPOUNDS
VACANCIES
X-RAY DIFFRACTION