Investigation on the Growth and Properties of Six Garnet Single Crystals with Large Lattice Constants

Abstract

Large lattice constant Y3Al5O12, Gd3Ga5O12 (GGG), Y3Sc2Ga3O12 (YSGG), Gd3Sc2Ga3O12, Ca0.4Mg0.25Zr0.65Gd2.6Ga4.1O12 (CaMgZr:GGG), and Gd1.17Y1.83Sc2Ga3O12 (GYSGG) substrate crystals with 2 in. in diameter are grown by the Czochralski (Cz) method, their physical, chemical, and optical properties are analyzed and compared in details. The X‐ray rocking curves (XRCs) illustrate that the as‐grown crystals possess high crystalline quality. The lattice constants of six crystals are calculated and that of GYSGG can be easily adjusted in the range of 1.2450–1.2565 nm by changing the Gd/Y proportion. The dislocation densities on the (111)‐crystalline face are about 102 cm−2 order of magnitude. The thermal conductivities of six crystals are measured to be 11.72, 8.98, 6.83, 5.45, 4.67, and 4.66 W m−1 K−1, respectively. It is found that the thermal expansion coefficients of six crystals can be reduced by annealing at 1273 K for 60 h. In addition, the transmission spectra show that the six crystals have excellent transparency and the coefficients of the Sellmeier equation are fitted by the calculated refractive indices. These results of the six crystals can provide the necessary parameters and references for the selection of suitable substrate materials or laser host crystals.