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

The ultrasonic parameters, the optical parameters along with the IR spectroscopy and magnetic susceptibility studies have been employed to explore the role of Gd2O3 in the structure of the glasses xGd2O3–60B2O3–10MoO3–(30-x)Bi2O3, with 0 ≤ x ≤ 7 mol %. IR analysis indicates that Gd2O3 is preferentially incorporated into the borate network-forming BO4 units. It is assumed that Bi2O3 and MoO3 enter the structure as modifiers in the form of BiO6 and MoO6 only. The compositional dependence of the mechanical and the optical parameters are interpreted in terms of the transformation of the structural units BO3 into BO4, 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 Gd3+ ions. The magnetic entropy change of the glasses was determined according to the temperature and magnetic field dependence of magnetization.

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