Dielectric and microstructural properties of YAG:Dy3+ ceramics

Yttrium aluminium garnet (Y₃Al₅O₁₂:YAG) singly doped with Dy³⁺ at different concentrations was prepared by solid state reactions using repeated heating cycles over the temperature range of 1300–1600 °C. X-ray powder diffraction analysis confirms the presence of a well-crystallized YAG perovskite phase with cubic structure (by Rietveld refinement). The rare earth dopant is successfully integrated into the YAG host lattice without any major changes in the original structure. The temperature dependence, up to 250 °C, of the conductivity, dielectric constant, dielectric loss, and loss tangent, at various frequencies of up to 5.0 MHz for undoped and doped crystals is compared to understand the electrical and structural characteristics. The experimental results reveal that Dy³⁺ dopants in YAG crystal significantly influence the conductivity, dielectric constant, and lossy mechanisms, which is probably due to the 3d-Al ions and 4f-Dy ions incorporated at different positions of both tetrahedral and octahedral symmetries in YAG:xDy³⁺ ceramics.