Optimum pyrochlore compositions for low thermal conductivity

• Published in: Philosophical magazine letters Vol. 84; no. 2; pp. 127 - 137
• Main Authors: Schelling ||, P. K., Phillpot ¶, S. R., Grimes, R. W.
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis Group 01-02-2004; Taylor & Francis
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves; Physics; Transport properties of condensed matter (nonelectronic); Pyrochlore; Inorganic compounds; Ternary compounds; Rare earths Oxides; Transition element compounds; Molecular dynamics method; Ionic radius; Rare earth compounds; Experimental study; Density; Disorder; Sound velocity; Thermal expansion; Thermal conductivity; Chemical composition; Metals Oxides; Self-diffusion
• ISSN: 0950-0839; 1362-3036
• DOI: 10.1080/09500830310001646699

The thermal conductivities of 40 pyrochlores with the composition A
2
B
2
O
7
(A = La, Pr, Nd, Sm, Eu, Gd, Y, Er or Lu; B = Ti, Mo, Sn, Zr or Pb) are predicted by molecular dynamics simulations. The trends in the behaviour can be fully understood in terms of the differences in the density and the speed of sound in the materials. Increased structural disorder, arising from O diffusion in most of the Pb-containing systems, leads to a further reduction in the thermal conductivity. We suggest strategies for lowering the thermal conductivity even further.