Thermal conductivity of transparent Y ₂ O ₃ , YAG, YSAG, and YGAG ceramics compared to YAG and sapphire single crystals

Thermal conductivity (<i>κ</i>) of Y₂O₃ ceramics, Y₃Al₅O₁₂ (YAG) ceramics, Y₃Sc₂Al₃O₁₂ (YSAG) ceramics, Y₃Ga₂Al₃O₁₂ (YGAG) ceramics, and sapphire compared to YAG single crystal from 160 K to 773 K was studied. <i>κ</i> of undoped Y₂O₃ ceramics, undoped YAG single crystal, 1at.% YAG single crystal, undoped YAG ceramics, 1at.% Nd:YAG ceramics, 1at.% Nd:YSAG ceramics, 1at.% Nd:YGAG ceramics, a-cut sapphire, and c-cut sapphire at 298 K were 10.7 W/mK, 10.4 W/mK, 9.85 W/mK, 9.75 W/mK, 9.28 W/mK, 6.41 W/mK, 6.74 W/mK, 33.8 W/mK, and 35.9 W/mK, respectively. <i>κ</i> of Y₂O₃ ceramics was found to be inferior to YAG single crystal below 252 K. We also investigated the linear thermal expansion coefficient (<i>α</i>) of YSAG and sapphire compared to YAG. <i>α</i> of 1at.% YAG ceramics, 1at.% Nd:YSAG ceramics, sapphire along a-axis, and sapphire along c-axis were 6.18×10^-6 /K, 6.46×10^-6 /K, 5.00×10^-6 /K, and 5.79×10^-6 /K, respectively.