Synthesis, structure, and physical properties of La[sub 3-x]M[sub x]Ni[sub 2]O[sub 7-[delta]] (M = Ca[sup 2+], Sr[sup 2+], Ba[sup 2+]; 0 < x [le] 0. 075)

Journal Article · Fri Jul 01 04:00:00 EDT 1994 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1994.1209· OSTI ID:6769856

Zhang, Z; Greenblatt, M ^[1]

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1. State Univ. of New Jersey, Piscataway, NJ (United States)

The synthesis, structure, and physical properties of La[sub 3-x]M[sub x]Ni[sub 2]O[sub 7-[delta]], with M = Ca[sup 2+], Sr[sup 2+], or Ba[sup 2+], and 0 < x [le] 0.075, were investigated. These compounds were prepared by a precursor method with tetramethyl ammonium hydroxide and were characterized by room temperature and high-temperature powder X-ray diffraction, TGA, electrical resistivity, and magnetic susceptibility measurements. The substituted compounds form with orthorhombic symmetry in space group Fmmm, similar to the as-prepared parent compound, La[sub 3]Ni[sub 2]O[sub 6.92]. As the amount of divalent alkaline earth metal substitution increases, the c cell parameter does not significantly change for Ca and increases significantly for Sr and Ba substitution, while the a and b cell parameters remain nearly unchanged for all cases. The observed trend in the c parameter is due to the increasing Ni[sup 3+] ion concentration for the case of Ca[sup 2+] substitution, while for Sr[sup 2+] and Ba[sup 2+] substitutions the effective larger size of the divalent cations is dominant. Significant oxygen deficiencies are noted in all of the as-prepared samples. However, upon high-pressure oxygen annealing, stoichiometric oxygen contents can be achieved. The room temperature resistivity of the as-prepared substituted compounds decreases relative to La[sub 3]Ni[sub 2]O[sub 6.92], and at x = 0.075 a semiconductor to metal transition is observed for all M. The magnetic susceptibility is nearly temperature independent in the temperature range 100-300 K, and paramagnetic behavior is observed below 100 K.

• OSTI ID: 6769856
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 111:1; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201 -- Ceramics
Cermets
&amp; Refractories-- Preparation &amp; Fabrication
360202* -- Ceramics
Cermets
&amp; Refractories-- Structure &amp; Phase Studies
360204 -- Ceramics
Cermets
&amp; Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL PREPARATION
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
GRAVIMETRIC ANALYSIS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
NICKEL COMPOUNDS
NICKEL OXIDES
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
QUANTITATIVE CHEMICAL ANALYSIS
RARE EARTH COMPOUNDS
SCATTERING
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SYNTHESIS
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION