Reduced thermal conductivity by nanoscale intergrowths in perovskite like layered structure La{sub 2}Ti{sub 2}O{sub 7}
- School of Engineering and Material Science, Queen Mary University of London, London E1 4NS (United Kingdom)
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Centre for Dielectric Research, Xi'an Jiaotong University, Xi'an, 710049 (China)
- School of Engineering and Applied Science, Aston University, Birmingham B4 7ET (United Kingdom)
- Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands)
The effect of substitution and oxidation-reduction on the thermal conductivity of perovskite-like layered structure (PLS) ceramics was investigated in relation to mass contrast and non-stoichiometry. Sr (acceptor) was substituted on the A site, while Ta (donor) was substituted on the B site of La{sub 2}Ti{sub 2}O{sub 7}. Substitution in PLS materials creates atomic scale disorders to accommodate the non-stoichiometry. High resolution transmission electron microscopy and X ray diffraction revealed that acceptor substitution in La{sub 2}Ti{sub 2}O{sub 7} produced nanoscale intergrowths of n = 5 layered phase, while donor substitution produced nanoscale intergrowths of n = 3 layered phase. As a result of these nanoscale intergrowths, the thermal conductivity value reduced by as much as ∼20%. Pure La{sub 2}Ti{sub 2}O{sub 7} has a thermal conductivity value of ∼1.3 W/m K which dropped to a value of ∼1.12 W/m K for Sr doped La{sub 2}Ti{sub 2}O{sub 7} and ∼0.93 W/m K for Ta doped La{sub 2}Ti{sub 2}O{sub 7} at 573 K.
- OSTI ID:
- 22413139
- Journal Information:
- Journal of Applied Physics, Vol. 117, Issue 7; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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