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

Abstract

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 P2O5 and 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.

Nanostructured PbS-Doped Inorganic Film Synthesized by Sol-Gel Route

“…The graphical determination of E g for the PbS-doped film is reported in [ 40 , 42 , 52 ]. The Mott and Davis/Tauc equation (4) was used to graphically establish the optical band gap, E g ( Figure 2 b).…”

“…The Mott and Davis/Tauc equation (4) was used to graphically establish the optical band gap, E g ( Figure 2 b). Thus, the Equation (4) [ 41 , 43 , 52 ] enables to determine the band gap, E g , where α is the absorption coefficient in dependence on wavelength, h is the Planck constant, ν is the light frequency, and n can be ½ for the allowed direct electron transition and 2 for the allowed indirect electron transition from the valence to the conduction band [ 53 ].…”

“…To verify the validity of the graphical method to determine E g and, respectively, λ g , the absorption spectrum fitting (ASF) method was applied [ 41 , 43 , 52 ] by means of which was determined and compared to the E g value determined by the Mott and Davis/Tauc law. Thus, the Tauc law is written as Equation (6) [ 41 , 43 , 52 ]: where α is the absorption coefficient, h is the Planck constant, c is the speed of light in vacuum equal to 3 × 10 8 m/s, λ is the wavelength, and E g is the band gap energy. Thus, the function is graphically represented in Figure 3 a.…”

Investigations Regarding the Addition of ZnO and Li2O-TiO2 to Phosphate-Tellurite Glasses: Structural, Chemical, and Mechanical Properties

“…Taking into consideration the nominal molar formula of the synthesized glass samples, it is possible to state that the vitreous network is built by metaphosphate chains and crosslinked metaphosphate chains formed by P-O-P, P-O-Te and Te-O-Te bonds, revealing the vitreous network-forming role of P 2 O 5 and TeO 2 [ 21 , 44 ].…”

Effect of B2O3 addition on thermal and optical properties of TeO2–ZnO–Bi2O3–TiO2 glasses

“…The sixth band at around 366-334 cm −1 may be attributed to symmetric stretching vibration of Bi-O atoms or stretching vibration of Bi-O-Bi [1,65]. The last two bands 287-250 cm −1 and 212-206 cm −1 may be attributed to vibrational move of ZnO group [58] and vibration mode of Te 2 based nanoclusters [66,67], respectively.…”