Structural and magnetotransport properties of the colossal magnetoresistance material Tl{sub 2}Mn{sub 2}O{sub 7}

Journal Article · Sat Mar 01 04:00:00 EST 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.55.6399· OSTI ID:505609

Shimakawa, Y; Kubo, Y; Manako, T; Sushko, Y V ^[1]; Argyriou, D N; Jorgensen, J D ^[2]

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1. Fundamental Research Laboratories, NEC Corporation, 34 Miyukigaoka, Tsukuba 305 (Japan)
2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

The crystal structure and its variation with temperature of the spin-charge coupled material Tl{sub 2}Mn{sub 2}O{sub 7} pyrochlore is investigated. Structure refinement from the neutron powder-diffraction data reveals that Tl{sub 2}Mn{sub 2}O{sub 7} has nearly stoichiometric composition and is crystallized in the cubic-pyrochlore-type structure with a characteristic Mn-O-Mn bond angle of 133{degree}. There is no structural anomaly associated with the change in magnetotransport properties at 142 K, suggesting weak spin-lattice and charge-lattice correlations. Despite the similarity of magnetotransport properties observed in the perovskite and the pyrochlore colossal magnetoresistance manganese oxides, the double-exchange mechanism, which is usually applied to the perovskite materials, does not seem to explain the behavior in the pyrochlore Tl{sub 2}Mn{sub 2}O{sub 7} compound. A superexchange-type interaction may stabilize the ferromagnetic ordering of Mn spins and cause the metallic conduction at low temperatures in Tl{sub 2}Mn{sub 2}O{sub 7}. {copyright} {ital 1997} {ital The American Physical Society}

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 505609
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 10 Vol. 55; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
LATTICE PARAMETERS
MAGNETORESISTANCE
MANGANESE OXIDES
NEUTRON DIFFRACTION
PEROVSKITES
SPIN-LATTICE RELAXATION
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
THALLIUM OXIDES