Optimal T{sub C} in Layered Manganites: Different Roles of Coherent and Incoherent Lattice Distortions

Journal Article · Sun Aug 01 00:00:00 EDT 1999 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.83.1223· OSTI ID:357323

Medarde, M; Mitchell, J F; Millburn, J E; Short, S; Jorgensen, J D ^[1]

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1. Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

Neutron powder diffraction experiments on layered manganites La{sub 2{minus}2x} Sr{sub 1+2x} Mn{sub 2}O {sub 7} (0.32{le}x{le}0.40) show that coherent lattice anomalies observed at the Curie temperature (lattice parameters, Mn-O bond lengths) reverse sign at x{approx}0.36 , coinciding with the maximum T{sub C}{approx}131 K . Remarkably, the anomalies are completely suppressed at this crossover composition. Incoherent distortions, as measured by anisotropic Debye-Waller factors, undergo an abrupt decrease below T{sub C} . The magnitude of this anomaly changes very little with x and does not display any sign reversal for x{approx}0.36 . {copyright} {ital 1999} {ital The American Physical Society}

• DOE Contract Number: W-31-109-ENG-38
• OSTI ID: 357323
• Journal Information: Physical Review Letters, Vol. 83, Issue 6; Other Information: PBD: Aug 1999
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
LANTHANUM OXIDES
STRONTIUM OXIDES
MANGANESE OXIDES
LATTICE PARAMETERS
NEUTRON DIFFRACTION
CURIE POINT
DEBYE-WALLER FACTOR
TEMPERATURE DEPENDENCE
CRYSTAL STRUCTURE