Influence of Li+ and Na+ Ions on the Dislocations Density of YbF3 Doped and LiF, NaF Codoped CaF2 Crystals
Pages 77-82
Andreea Pruna, Marius Stef, Gabriel Buse, Irina Nicoara
Abstract. Various concentrations YbF3 -doped CaF2 and Li- (Na)- codoped crystals have been grown using the conventional Bridgman method. Transparent colorless crystals were obtained in graphite crucible in vacuum (~ 10-1 Pa) using a shaped graphite furnace [1]. The crystals have been cooled to room temperature using an established procedure. In order to study the etch pits morphology and the dislocations density we used the etching method [2]. This method consists in immersing the cleaved sample in 4NHCl at 600C for 5 minutes. Small pits are developed at the emergence points of the dislocations. The etch pits have triangular or hexagonal shapes, depending on the dopant type [3]. The dislocations density depends also on the dopant or on the codopant types.