Nickel ion—A structural probe in BaO–Al2O3–P2O5 glass system by means of dielectric, spectroscopic and magnetic studies

Spectroscopic and dielectric properties of crystallized PbO–Sb2O3–As2O3:NiO glass system

“…The observed dielectric relaxation effects in PbO-Sb 2 O 3 -As 2 O 3 glasses crystallized with different concentrations of NiO may be attributed to the association of octahedrally positioned Ni 2+ ions with a pair of cationic vacancies as observed in a number of conventional glasses, glass ceramics and crystals that contain divalent positive ions as reported before [38].…”

Role of Al coordination in barium phosphate glasses on the emission features of Ho3+ ion in the visible and IR spectral ranges

“…This region may also consist of bands due to pyrophosphate groups (P 2 O 7 4 À ) [22,23]. Two new bands at 773 and 466 cm À 1 idnetified due to AlO 4 structural and AlO 6 structural units respectively [24][25][26] have also been observed. As the concentration of Al 2 O 3 is increased up to 3.0 mol%, the bands due to AlO 6 units and due to PO 2 À groups are observed to grow whereas the bands due to PO 4 3 À groups and AlO 4 structural units exhibit a slight decay.…”

“…10. However, previous studies have also pointed out that Al (6) dominates the glass structure when Al 2 O 3 is present in low concentrations and Al(4) forms only at higher Al 2 O 3, content [25,26]. For example, if we assume isotropic bonding, each Al(4) contributes 0.75 valance units to its four nearest neighbouring oxygens, Al(6) contributes 0.5 valance units to its six nearest neighbouring oxygens, and P(4) contributes 1.25 valence units to its four nearest neighbouring oxygens.…”

Role of Al2O3 in upconversion and NIR emission in Tm3+ and Er3+ codoped calcium fluoro phosphorous silicate glass system

“…2) exhibited vibrational bands at 1293 cm À 1 (due to anti-symmetrical vibrations of PO À 2 =P ¼ O stretching vibrations), 1089 cm À 1 (due to symmetric stretching vibrations of PO 3À 4 group) and 934 cm À 1 (due to P-O-P asymmetric bending vibrations) [37,38]. Band due to AlO 4 structural units is observed at about 820 cm À 1 [39][40][41]; in the same region the bands due to phosphate, silicate structural units are also present. Hence this band may be attributed to the common stretching vibrations of AlO 4 , PO 4 and SiO 4 structural units.…”