Evidence of the inhomogeneous Ce³⁺ distribution across grain boundaries in transparent polycrystalline Ce³⁺-Doped (Gd,Y) ₃Al₅O₁₂ garnet optical ceramics

This paper characterizes the inhomogeneous rare earth activator distribution across grain boundaries in transparent rare earth doped optical ceramics. Ce³⁺ has been selected due to its high intensity fluorescence in visible range under blue or UV excitations, especially in (Gd,Y)₃Al₅O₁₂ disordered garnet ceramic for scintillator application. Optical spectroscopy and visualization of grains and grain boundaries based on spatially resolved techniques as imaging confocal microscopy (ICM) and transmission electronic microscopy (TEM) have been used for 0.5% Ce³⁺-doped (Gd,Y)₃Al₅O₁₂ ceramic. A strong Ce³⁺ segregation and spatial distribution between grains and grain boundaries were observed.