307 research outputs found
Nanoscale clusters in the high performance thermoelectric AgPbmSbTem+2
The local structure of the AgPbmSbTem+2 series of thermoelectric materials
has been studied using the atomic pair distribution function (PDF) method.
Three candidate-models were attempted for the structure of this class of
materials using either a one-phase or a two-phase modeling procedure. Combining
modeling the PDF with HRTEM data we show that AgPbmSbTem+2 contains nanoscale
inclusions with composition close to AgPb3SbTe5 randomly embedded in a PbTe
matrix.Comment: 7 pages, 5 figures, 2 tables, submitted to PR
Strain, nano-phase separation, multi-scale structures and function of advanced materials
Recent atomic pair distribution function results from our group from
manganites and cuprate systems are reviewed in light of the presence of
multi-scale structures. These structures have a profound effect on the material
propertiesComment: 17 pages, 7 figures, 41 references, ICTP02 conference, to be
published by World Scientifi
Structural compliance, misfit strain and stripe nanostructures in cuprate superconductors
Structural compliance is the ability of a crystal structure to accommodate
variations in local atomic bond-lengths without incurring large strain
energies. We show that the structural compliance of cuprates is relatively
small, so that short, highly doped, Cu-O-Cu bonds in stripes are subject to a
tensile misfit strain. We develop a model to describe the effect of misfit
strain on charge ordering in the copper oxygen planes of oxide materials and
illustrate some of the low energy stripe nanostructures that can result.Comment: 4 pages 5 figure
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