Investigations on the structural, electrical and magnetic properties of Sr substituted Ln[sub 2]NiO[sub 4] (Ln = Pr, Sm, Gd)

Journal Article · Sun Aug 01 04:00:00 EDT 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1237· OSTI ID:7284055

Chen, S C; Ramanujachary, K V; Greenblatt, M ^[1]

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

Solid solutions of Ln[sub 2[minus]x]Sr[sub x]NiO[sub 4[+-][delta]](Ln = Pr, Sm) and GdSrNiO[sub 4] were synthesized in air using conventional solid state methods and were characterized by powder X-ray diffraction, TGA, electrical resistivity, DSC, Seebeck coefficient, and magnetic susceptibility measurements. A structural transition from orthorhombic to tetragonal was observed at x [approximately] 0.2 for Pr and 0.8 for Sm. For both series of compounds (Ln = Pr, Sm), the tetragonal unit cell parameters a[sub t] and c as functions of x display sharp minima and maxima, respectively, at x [approximately] 0.6. The tetragonality ratio, c/a[sub t], shows a maximum at x [approximately] 0.6. All the compounds are semiconducting from room temperature down to 25 K, except SmSrNiO[sub 4] and GdSrNiO[sub 4], which exhibit a degenerate semiconductor to semiconductor transition at [approximately] 292 K and [approximately] 260 K, respectively. Seebeck measurements indicate that electrons are the dominant carriers of the samples, except Sm[sub 2[minus]x]Sr[sub x]NiO[sub 4[+-][delta]] for x = 0l8 and 1.0, follow Curie-Weiss behavior in the temperature range 100-300K with no evidence of long range magnetic ordering. The effect of Sr[sup 2+] substitution on the structural, electrical, and magnetic properties of Ln[sub 2[minus]x]Sr[sub x]NiO[sub 4[+-][delta]] (Ln = Pr, Sm) is discussed in terms of the mixed-valent character of Ni[sup 2+/3+] ions, the Ln-O vs Ni-O bond competition along the crystallographic c-axis, the size effect, the local distortion of NiO[sub 6] octahedra, and a configurational transition in the d-manifold of nickel ions.

• OSTI ID: 7284055
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 105:2; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
CALORIMETRY
CHALCOGENIDES
CHEMICAL ANALYSIS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
GRAVIMETRIC ANALYSIS
LATTICE PARAMETERS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MATERIALS
NICKEL COMPOUNDS
NICKEL OXIDES
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
QUANTITATIVE CHEMICAL ANALYSIS
RARE EARTH COMPOUNDS
SAMARIUM COMPOUNDS
SAMARIUM OXIDES
SEEBECK EFFECT
SEMICONDUCTOR MATERIALS
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TETRAGONAL LATTICES
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
TRANSITION ELEMENT COMPOUNDS