Transport and magnetism in La{sub 2/3}Ca{sub 1/3}(Mn{sub 1{minus}x}Co{sub x})O{sub 3} and La{sub 2/3}Ca{sub 1/3}(Mn{sub 1{minus}x}Ni{sub x})O{sub 3} (abstract)

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.364929· OSTI ID:496542

Rubinstein, M; Tritt, T M; Synder, J E ^[1]

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1. U.S. Naval Research Laboratory, Washington, D.C. 20375 (United States)

La{sub 2/3}Ca{sub 1/3}MnO{sub 3} is a strong double-exchange ferromagnet where the ratio of La{sup 3+}{endash}Ca{sup 2+} ions has been chosen to maximize its favorable magnetic and transport properties. The Mn ion is unique as an effective participant in the double-exchange process. It is of interest to add Ni or Co atoms substitutionally for Mn in the form of La{sub 2/3}Ca{sub 1/3}(Mn{sub 1{minus}x}Co{sub x})O{sub 3} and La{sub 2/3}Ca{sub 1/3}(Mn{sub 1{minus}x}Ni{sub x})O{sub 3} in order to determine the relative importance of the double-exchange interaction as the Mn concentration is reduced. Powder x-ray diffraction reveals we can retain the original orthorhombic structure of La{sub 2/3}Ca{sub 1/3}MnO{sub 3} (with up to 50{percent} Co or Ni substitution) by a series of anneals at 1300{degree}C followed by repeated grindings. We have investigated the magnetization, electrical conductivity, and thermopower of these mixed transition-metal perovskites. For La{sub 2/3}Ca{sub 1/3}(Mn{sub 1{minus}x}Co{sub x})O{sub 3}, the magnetization decreases with added Co, but ferromagnetism is retained (at least up to 50{percent} Co). Although metallic conductivity is still present at 10{percent} Co concentration, these Co{endash}Mn perovskites become insulating for x{ge}0.2. For La{sub 2/3}Ca{sub 1/3}(Mn{sub 1{minus}x}Ni{sub x})O{sub 3}, the metallic state is retained at least until x=0.5. The magnetic properties exhibit spin-glasslike behavior for x{ge}0.25. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 496542
• Report Number(s): CONF-961141--
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 81; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CALCIUM COMPOUNDS
CALCIUM OXIDES
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
FERROMAGNETIC MATERIALS
GRINDING
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MAGNETIC PROPERTIES
MAGNETIZATION
MANGANESE OXIDES
NICKEL ADDITIONS
PEROVSKITES
THERMOELECTRIC PROPERTIES
X-RAY DIFFRACTION