Effect of 3d-transition metal ions on the structural, optical and magnetic properties of chromium-bearing barium borate glass

Abstract

This article reports the effect of 3d-transition metal ions on the optical features of chromium ions bearing glass host. Interestingly, this study unveiled the charge transfer of Cr ions at high energy (at 347 nm), which is often hidden in earlier reports due to its vicinity to the glass edge, and its immersion in the lattice band of the glass host. In addition to the well-defined charge transfer at low energy (at 378 nm). In this vein, glass composition [(TM)1−(B2O3)80−(BaO)18.7−(Cr2O3)0.3], where TM is the transition metal ions in their oxide form, was prepared via the melt-quenching method at about 1100 °C. X-ray diffraction patterns confirmed the amorphous structure of the glass, and the chemical composition was examined using energy-dispersive X-ray spectra. The decrease in density (from 2.74 gcm−3 to 2.59 gcm−3) and the increase in molar volume (from 31.92 cm3mol−1 to 34.32 cm3mol−1) were demonstrated. Moreover, the refractive index is attained at an average value (1.50). The glass structure was studied using infrared spectroscopy, which elucidated an increase in N4 (33.2%–37.5 %) and an increase in NBO (15.3%-18.4 %). Bewitshingly, the charge transfer of Cr6+ ions, at high energy (347 nm), was explored. This, in turn, leads to a proper investigation of glass absorption edges that undergo a blue shift of about 1.25 eV. Adding 3d-transition metal ions affects crystal field splitting energy and interelectronic interaction within the d-orbitals of Cr ions. Finally, ESR data confirmed the Cr5+ state (with ESR signal at 1.92) and Cr3+ state (with ESR signal at 4.6, 4.07 and 2.04) of chromium ions. Such a cohesive investigation of the structure, optical and magnetic properties of 3d-transition metal ions-bearing chromium barium borate glass paved the route toward utilization of these samples in the optoelectronic realm.