Thermal properties of the pyrochlore, Y2Ti2O7

摘要: The thermal conductivity and heat capacity of high-purity single crystals yttrium titanate, Y{sub 2}Ti{sub 2}O{sub 7,} have been determined over the temperature range 2 K<=T<=300 K. experimental is in very good agreement with an analysis based on three acoustic modes per unit cell (with Debye characteristic temperature, theta{sub D}, ca. 970 K) assignment remaining 63 optic modes, as well a correction for C{sub p}-C{sub v}. From integrated data, enthalpy entropy relative to absolute zero, are, respectively, H(T=298.15 K)-H{sub 0}=34.69 kJ mol{sup -1} S(T=298.15 K)-S{sub 0}=211.2 J K{sup -1}. shows peak at D}/50, highly purified crystal which phonon mean free path about 10 {mu}m defect/boundary low-temperature limit. room-temperature 7} 2.8 W m{sup -1}, close calculated theoretical conductivity, kappa{sub min}, fully coupled phonons high temperatures. - Graphical Abstract: K.more » limit.« less