Crystallization studies on rare-earth co-doped fluorozirconate-based glasses

This work focuses on the structural changes of barium chloride (BaCl₂) nanoparticles in fluorochlorozirconate-based glass ceramics when doped with two different luminescent activators, in this case rare-earth (RE) ions, and thermally processed using a differential scanning calorimeter. In a first step, only europium in its divalent and trivalent oxidation states, Eu²⁺ and Eu³⁺, is investigated, which shows no significant influence on the crystallization of hexagonal phase BaCl₂. However, higher amounts of Eu²⁺ increase the activation energy of the phase transition to an orthorhombic crystal structure. In a second step, nucleation and nanocrystal growth are influenced by changing the structural environment of the glasses by co-doping with Eu²⁺ and trivalent Gd³⁺, Nd³⁺, Yb³⁺, or Tb³⁺, due to the different atomic radii and electro-negativity of the co-dopants.