A New Zinc Phosphate-Tellurite Glass for Magneto-Optical Applications

• Main Authors: Mihail Elisa, Raluca Constantina Stefan, Ileana Cristina Vasiliu, Stefan Marian Iordache, Ana-Maria Iordache, Bogdan Alexandru Sava, Lucica Boroica, Marius Catalin Dinca, Ana Violeta Filip, Aurelian Catalin Galca, Cristina Bartha, Nicusor Iacob, Madalin Ion Rusu, Mihai Eftimie, Victor Kuncser
• Format: Article
• Language: English
• Published: MDPI AG 2020-09-01
• Series: Nanomaterials
• Subjects: glass; diluted ferromagnetism, optical spectroscopies, magneto-optical functionalities
• Online Access: https://www.mdpi.com/2079-4991/10/9/1875

This work investigates the structural, magnetic and magneto-optical properties of a new zinc phosphate-tellurite glass belonging to the 45ZnO-10Al₂O₃-40P₂O₅-5TeO₂ system. The glass was prepared by a wet method of processing the starting reagents followed by suitable melting–stirring–quenching–annealing steps. Specific parameters such as density, average molecular mass, molar volume, oxygen packaging density, refractive index, molar refractivity, electronic polarizability, reflection loss, optical transmission, band gap and optical basicity have been reported together with thermal, magnetic and magneto-optical characteristics. Absorption bands appear in the blue and red visible region, while over 600 nm the glass becomes more transparent. FTIR and Raman spectra evidenced phosphate-tellurite vibration modes proving the P₂O₅and TeO₂ network forming role. Magnetic measurements reveal the diamagnetic character of the Te-doped glass with an additional weak ferromagnetic signal, specific to diluted ferromagnetic oxides. Positive Faraday rotation angle with monotonous decreasing value at increasing wavelength was evidenced from magneto-optical measurements. The final product is a composite material comprising of a non-crystalline vitreous phase and Te-based nanoclusters accompanied by oxygen vacancies. The metallic-like Te colloids are responsible for the dark reddish color of the glass whereas the accompanying oxygen vacancies might be responsible for the weak ferromagnetic signal persisting up to room temperature.