Structure and properties of Li2–2xMg2+x(MoO4)3 crystals activated by copper ions

Abstract

By the low-gradient Čzochralski method, both undoped and copper ion activated Li_2–2xMg_2+x(MoO₄)₃ crystals are grown. The charge state and structural position of impurity copper ions are determined using EPR. Investigations of the luminescence properties reveal that luminescence with a maximum at λ = 520 nm is observed for Li_2–2xMg_2+x(MoO₄)₃ crystals. A decrease in the temperature increases the intensity of this luminescence. It is found that the doping of Li_2–2xMg_2+x(MoO₄)₃ crystals with copper ions also increases the luminescence intensity with a maximum at λ = 520 nm. It is supposed that cation vacancies, which provide the charge compensation when copper ions substitute for lithium ions, are responsible for the luminescence.