Investigation on the structural and electrical properties of NdSrNi{sub 1-x}Cr{sub x}O{sub 4+{delta}} (0.1<=x<=0.9) system

Journal Article · Sat May 15 00:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.03.028· OSTI ID:21372610

Jammali, Manel; Chaker, H; Cherif, K ^[1]

---

1. Unite de Recherche de Chimie des Materiaux (02/UR/12-01), ISSBAT, Universite de Tunis El Manar, 9 Avenue Dr. Zoheir Safi, 1006 Tunis (Tunisia)

The phases NdSrNi{sub 1-x}Cr{sub x}O{sub 4+{delta}} (0.1<=x<=0.9) have been synthesized by modified sol-gel method and subsequent annealing at 1250 deg. C in 1 atm of flowing argon. X-ray diffraction (XRD) analysis and electrical resistivity have been measured at room temperature. Rietveld refinement shows that all compositions with x>0.1 were found to crystallize in the tetragonal K{sub 2}NiF{sub 4} type structure in the space group I4/mmm, while for x=0.1, a mixture of two phases with the tetragonal space group I4/mmm and the orthorhombic space group Fmmm. Variations of a and c parameters show a complex behavior with increasing chromium content. It was established that compounds with chromium content less then x<=0.5 are oxygen-deficient, while for x>0.5 the sample are oxygen-overstoichiometric. The NdSrNi{sub 0.5}Cr{sub 0.5}O{sub 4+{delta}} compound exhibits semiconductive behavior and the electrical transport mechanism agrees with the non-adiabatic small polaron hopping model in the temperature ranges 298-493, 493-573 and 573-703 K separately. - Graphical abstract: The X-ray pattern of the x=0.1 sample showed a shift of some Bragg reflections that was indicative of a unit cell of lower symmetry. Two distortions of the I4/mmm K{sub 2}NiF{sub 4} aristotype cell to orthorhombic symmetry are known, Fmmm and I mmm, depending on which of the <1 0 0> and <1 1 0> sets of mirror planes and twofold axes are lost together with the fourfold axis when the symmetry is lowered

• OSTI ID: 21372610
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 5; Other Information: DOI: 10.1016/j.jssc.2010.03.028; PII: S0022-4596(10)00118-0; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANNEALING
ARGON
BRAGG REFLECTION
CHROMIUM COMPOUNDS
ELECTRIC CONDUCTIVITY
NEODYMIUM COMPOUNDS
NICKEL COMPOUNDS
ORTHORHOMBIC LATTICES
SOL-GEL PROCESS
SPACE GROUPS
STRONTIUM COMPOUNDS
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 1000-4000 K
TETRAGONAL LATTICES
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRICAL PROPERTIES
ELEMENTS
FLUIDS
GASES
HEAT TREATMENTS
NONMETALS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
RARE GASES
REFLECTION
SCATTERING
SYMMETRY GROUPS
TEMPERATURE RANGE
TRANSITION ELEMENT COMPOUNDS