Nb2O5 improved photoluminescence, magnetic and Faraday rotation properties of magneto-optical glasses

Abstract The high polarizability, low photon energy, high non-linear character and dual functions in glass network make diamagnetic Nb2O5 attractive to magneto optical glass based photonics and sensing devices. In this paper, we report for the first time the influence of Nb2O5 on glass formation, structure, photoluminescence, magnetic and Faraday rotation properties of heavy metal oxide diamagnetic glass. Results suggested that Nb2O5 doping amount greatly influenced its coordination numbers and roles in glass network. Ni2O5 amount ≤ 5 mol% in glass presented in NiO4 which played glass former role and strengthened the PbO4, BiO6, BiO3 and BO3 units composed glass network connectivity, transparent and homogeneous glasses were obtained. DSC measurement showed that the 1%, 2% and 5%Nb2O5 doping increased the Tg and thermal stability of glass. Nb2O5 doping amount higher than 5% presented as NiO6 units which played glass modifier role in glass which distorted glass structure and produced BiNbO4 and Nb2O5 crystalline. A red-shift of absorption edge from 500 nm to 529 nm was observed for Nb2O5 doped glasses. Due to the high optical basicity of host, niobium existed in glass only as Ni5+, and the electron transfers between O2– and Nb5+ displayed two broad emission bands centered at 376 cm and 493 nm (excited at 267 nm) in photoluminescence spectra. 5Nb2O5–5B2O3–45PbO–45Bi2O3 glass exhibited significant thermal stability (100 °C), good photoluminescence, high magnetic susceptibility (57.32 × 10−6 emu/g), and Verdet constant (0.1713 min/G.cm at 633 nm). The novelty of this work is to combine the high polarizability, dual roles properties of Nb2O5 and the high optical basicity of diamagnetic host glass to achieve a diamagnetic valence of Nb and enhance Faraday rotation performance.