Optimum pyrochlore compositions for low thermal conductivity

Abstract The thermal conductivities of 40 pyrochlores with the composition A2B2O7 (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. Acknowledgements We are happy to acknowledge useful discussion with J. A. Eastman. P. K. S. and S. R. P. are supported by the US Department of Energy, Basic Energy Sciences-Materials Science, under contract W-31-109-Eng-38. R. W. G. gratefully acknowledges support through the European Office of Aerospace Research and Development (EOARD) contract F61775-00-WE016. Notes ¶Present address: Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA. ‖Present address: Advanced Material Processing and Analysis Center, Department of Physics, University of Central Florida, Orlando, Florida 32816, USA. Email: pschell@mail.ucf.edu. ‖Present address: Advanced Material Processing and Analysis Center, Department of Physics, University of Central Florida, Orlando, Florida 32816, USA. Email: pschell@mail.ucf.edu. Additional informationNotes on contributorsR. W. Grimes ¶Present address: Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA. ‖Present address: Advanced Material Processing and Analysis Center, Department of Physics, University of Central Florida, Orlando, Florida 32816, USA. Email: pschell@mail.ucf.edu.