Effects of rare-earth doping on thermal conductivity in Y3Al5O12 crystals

We have proposed a new model of thermal conductivity, which is applicable for both single-crystalline and poly-crystalline Y3Al5O12. This model can explain the temperature dependence of thermal conductivity from room temperature to 200 °C. By comparing the measured value of thermal conductivity in Nd3+ and Yb3+-doped Y3Al5O12, we can involve effects of rare-earth concentration into our model. It has been confirmed that there is no difference in characteristics of thermal conduction between single- and poly-crystalline Y3Al5O12. While the influence of grain-boundary in poly-crystals has been considered to be effective only in low temperature condition (below 100 K), we confirmed that the difference between thermal conductivity of single- and poly-crystalline Y3Al5O12 remains several percent even at room temperature when the grain size is enough small. It has been demonstrated that our model is quite useful for thermal analysis of laser cavities in high-power density by using a single-crystalline and poly-crystalline Y3Al5O12.