Synthesis, structure and spectral-luminescent properties of nickel doped magnesium aluminosilicate glass-ceramic

Background. Glass-ceramics (GC) has attracted researchers for over 50 years due to its unique physical properties. Thermal treatment of initial glass interrupted at a particular stage is the main way to obtain transparent GC with nanoscale inclusions. Combined XRD, SAXS and optical spectroscopy studies allow to investigate the occurring processes of nucleation and phase separation of GC. The aim of this work is to obtain$Ni^{2+}$-doped transparent magnesium aluminosilicate GC and study its physical properties. Materials and methods. Glasses of $28MgO-10Al_2O_3-8TiO_2-xGa_2O_3-(54-x)SiO_2+y NiO$ mol $\%$ systems were used as the host of $Ni^{2+}$ (where x=0, 3, 5; y=0.001, 0.01, 0.1.). Nanostructured GC was obtained by sequential high temperature annealing of initial glass at temperatures 720 $^{\circ}С$ and 740 $^{\circ}С$, 760 $^{\circ}С$ and 780 $^{\circ}С$ for 2-5 hours. The phase composition of formed crystallites was determined by diffractometer PANanalitical Empyrean. The absorption spectra were carried out by dual-beam spectrophotometer Perkin Elmer Lambda 950. The GC structure was investigated by the small-angle X-ray scattering (SAXS) diffractometer Hecus S3-MICRO. Results. The article presents the results of the study of formation of the crystalline phase in $Ni^{2+}$-doped magnesium aluminosilicate GC in the course of sequential high temperature treatment. Addition of $Ga_2O_3$ in the glass matrix leads to suppression of the magnesium alumotitanate crystalline phases and to the increase of the aluminum-magnesium spinel phase. It is shown that the crystalline phase concentration and radius of gyration of inhomogeneities increase with growth of temperature of isochoric annealing. The radius of gyration of inhomogeneities changes from 20 to 120 Å with temperature growth. Reduction of NiO concentration leads to the increase of the radius of gyration of scattering domains. The luminescence spectra of GC are characterized by width peak centered at 1300-1400 nm. The half-width of the peak is 350 nm. Conclusions. The authors obtained the $Ni^{2+}$-doped transparent magnesium aluminosilicate GC. The influence of gallium oxide on the kinetics of crystalline phase deposition was investigated. It is shown that the GC, obtained by controlled crystallization of optical glasses, has a wide range of luminescence centered at 1300-1400 nm that matches with the telecommunication window.