Perovskite-type oxides. 1: Structural, magnetic, and morphological properties of LaMn[sub 1[minus]x]Cu[sub x]O[sub 3] and LaCo[sub 1[minus]x]Cu[sub x]O[sub 3] solid solutions with large surface area

Journal Article · Wed Sep 01 00:00:00 EDT 1999 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1999.8326· OSTI ID:6108652

Porta, P; De Rossi, S; Faticanti, M; Minelli, G; Pettiti, I ^[1]; Lisi, L ^[2]; Turco, M ^[3]

---

1. Univ. La Sapienza, Rome (Italy). Dept. di Chimica
2. CNR, Naples (Italy). Ist. di Ricerche Sulla Combustione
3. Univ. Federico II, Naples (Italy). Dept. di Ingegneria Chimica

Perovskite-type compounds of general formula LaMn[sub 1[minus]x]Cu[sub x]O[sub 3] and LaCo[sub 1[minus]x]Cu[sub x]O[sub 3] (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared by calcining the citrate gel precursors at 823, 923, and 1073 K. The decomposition of the precursors was followed by thermal analysis and the oxides were investigated by means of elemental analysis (atomic absorption and redox titration), X-ray powder diffraction, BET surface area, X-ray absorption (EXAFS and XANES), electron microscopy (SEM and TEM), and magnetic susceptibility. LaMn[sub 1[minus]x]Cu[sub x]O[sub 3] samples are perovskite-like single phases up to x = 0.6. At x = 0.8 CuO and La[sub 2]CuO[sub 4] phases are present in addition to perovskite. Magnetic susceptibility studies show a ferromagnetic behavior that decreases with increase in x. Materials with not very clear morphology and crystals with definite structure are distinguishable by SEM for samples calcined at 1073 and at 1273 K, respectively. TEM patterns, for samples calcined at 1073 K, evidence almost regular hexagonal prismatic crystals connected to form linked structures and some spotty crystals, suggesting short-range ordered local defects. For copper-containing samples, calcined at 1273 K, a higher degree of defectivity (probably associated with the interaction of anion vacancies) and the occurrence of planar faults are shown by TEM.

• OSTI ID: 6108652
• Journal Information: Journal of Solid State Chemistry, Vol. 146:2; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COBALT OXIDES
COPPER OXIDES
CRYSTAL STRUCTURE
EXPERIMENTAL DATA
LANTHANUM OXIDES
LATTICE PARAMETERS
MAGNETIC PROPERTIES
MANGANESE OXIDES
MICROSCOPY
PEROVSKITES
SOLID SOLUTIONS
X-RAY DIFFRACTION
CHALCOGENIDES
COBALT COMPOUNDS
COHERENT SCATTERING
COPPER COMPOUNDS
DATA
DIFFRACTION
DISPERSIONS
INFORMATION
LANTHANUM COMPOUNDS
MANGANESE COMPOUNDS
MINERALS
MIXTURES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SCATTERING
SOLUTIONS
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360204 - Ceramics
Cermets
& Refractories- Physical Properties