Spectroscopic, mechanical and magnetic characterization of some bismuth borate glasses containing gadolinium ions

• Published in: Solid state sciences 2010-08, Vol.12 (8), p.1426-1434
• Main Authors: Saddeek, Yasser B., Yahia, I.S., Aly, K.A., Dobrowolski, W.
• Format: Article
• Language: English
• Subjects: Bismuthate glasses; Bonding strength; Borate glasses; Borates; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; Cross-disciplinary physics: materials science; rheology; Density; Elastic properties; Entropy; Entropy change; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Fullerenes and related materials; Glass; Infrared and raman spectra and scattering; Infrared radiation; Magnetic characterization; Magnetic permeability; Magnetic properties and materials; Magnetic properties of nanostructures; Magnetic susceptibility; Magnetization; Materials science; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Specific phase transitions; Spectroscopy; Structural transitions in nanoscale materials
• ISSN: 1293-2558; 1873-3085
• DOI: 10.1016/j.solidstatesciences.2010.05.023

The ultrasonic parameters, the optical parameters along with the IR spectroscopy and magnetic susceptibility studies have been employed to explore the role of Gd 2O 3 in the structure of the glasses xGd 2O 3–60B 2O 3–10MoO 3–(30- x)Bi 2O 3, with 0 ≤  x ≤ 7 mol %. IR analysis indicates that Gd 2O 3 is preferentially incorporated into the borate network-forming BO 4 units. It is assumed that Bi 2O 3 and MoO 3 enter the structure as modifiers in the form of BiO 6 and MoO 6 only. The compositional dependence of the mechanical and the optical parameters are interpreted in terms of the transformation of the structural units BO 3 into BO 4, the increase in the number of bridging oxygen atoms, and the substitution of high bond strength Gd–O, in the place of low bond strength Bi–O bond. The results of the magnetic susceptibility reveal the paramagnetic behavior as described by the Curie-Weiss law and indicating the presence of weak antiferromagnetic exchange interactions between Gd 3+ ions. The magnetic entropy change of the glasses was determined according to the temperature and magnetic field dependence of magnetization. [Display omitted]