Metal-insulator transitions in anion-excess LaMnO[sub 3+[delta]] controlled by the Mn[sup 4+] content

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

DOI:https://doi.org/10.1006/jssc.1993.1142· OSTI ID:6254384

Verelst, M; Rangavittal, N; Rao, C N.R. ^[1]; Rousset, A ^[2]

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1. Indian Inst. of Science, Bangalore (India)
2. Universite Paul Sabatier, Toulouse (France)

LaMnO[sub 3+[delta]] samples with Mn[sup 4+] content up to 50% have been prepared by different methods. The structure of LaMnO[sub 3+[delta]] changes from orthorhombic to cubic (via rhombohedral) with increase in the Mn[sup 4+] content. LaMnO[sub 3+[delta]] samples containing greater than 20% Mn[sup 4+] are ferromagnetic and show resistivity maxima at a temperature T[sub t] which is close to the ferromagnetic Curie temperature. The resistivity maximum is due to the occurrence of a metal-insulator transition. In samples heated to the same temperature, the value of T[sub t] increases with % Mn[sup 4+]. For a given sample, T[sub t] increases with the temperature of heat treatment due to the increase in particle size. The onset of ferromagnetism in LaMnO[sub 3+[delta]] accompanied by an insulator-metal transition is similar to that found in La[sub 1[minus]x]Ca[sub x]MnO[sub 3] and La[sub 1[minus]x]Sr[sub x]CoO[sub 3]. 10 refs., 5 figs., 3 tabs.

• OSTI ID: 6254384
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 104:1; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ANIONS
CHALCOGENIDES
CHARGED PARTICLES
CONCENTRATION RATIO
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
CURIE POINT
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FERROMAGNETISM
IONS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MAGNETISM
MANGANESE COMPOUNDS
MANGANESE OXIDES
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SIZE
STOICHIOMETRY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE