Microstructural control and tuning of thermal conductivity in   La0.67Ca0.33MnO3+/-\delta
  Manganites are one of only a small number of material families currently being trialled as room temperature magnetic refrigerants. Here we examine the dependence of the thermal conductivity, K, of La0.67Ca0.33MnO3+/-{\delta} as a function of density, grain size and silver impregnation around room temperature. We use a simple effective medium model to extract relevant trends in the data and demonstrate a threefold increase in thermal conductivity by silver impregnation. 
J. A. Turcaud, K. Morrison, A. Berenov, N. McN. Alford, K. G.   Sandeman, L. F. Cohen
cond-mat.str-el cond-mat.mtrl-sci