EPR and Optical Absorption Studies of Cu2+ in Boro-Arsenate Glasses

Abstract

Electron paramagnetic resonance (EPR) and optical absorption studies of xMgO-(25-x) Li 2 O-50B 2 O 3 -25As 2 O 3 glasses were made by introducing Cu 2+ as a spin probe. The EPR spectra of all the glass samples recorded at X-band frequencies have similar spectral features. The Cu 2+ ions are in well-defined axial sites, but subjected to small distortion leading to the broadening of the spectra. The spin-Hamiltonian parameter values indicate that the ground state of Cu 2+ is d x2-y2 and the site symmetry around Cu 2+ ions is tetragonal distorted octahedral. The optical absorption spectra exhibited a broadband corresponding to the d-d transition bands of Cu 2+ ion. By correlating EPR and optical data, the bond parameters were evaluated and the values show purely ionic nature for the in-plane σ bonding and in-plane π bonding. The out-of-plane π bonding is moderately covalent.

Bandgap Engineering of Lead-Free Double Perovskite Cs2AgInCl6 Nanocrystals via Cu2+-Doping

“…There is strong interest to replace Pb 2+ ions with other less toxic metal ions such as Sn 2+ or Ge 2+ . Unfortunately, the corresponding halide perovskites show instability due to the oxidation of both Sn 2+ and Ge 2+ to their respective 4 + states. − …”

“…The isotopic abundance of 63 Cu is 68.94%, whereas the 65 Cu amounts to only 31.06%. The EPR spectrum of Cu 2+ ought to consist of eight hyperfine lines, including four parallel and four vertical components. ,− The EPR spectra show four parallel components in the low field region. However, the perpendicular component is not resolved, resulting in broader lines in the high field region.…”

ESR and magnetic studies of nickel ions doped P2O5–ZnO–Na2O glassy system

“…The NiO at 1 mol.% sample has the same three octahedral bands and does not exhibit any tetrahedral band. The (Oh) band at 438 nm is associated to the spin allowed transition 3 A 2g (F ) → 1 T 1g (P ), while the band at 803 nm can be attributed to the existence of Ni 2+ ion (3d 8 configuration) of the spin allowed transition 3 A 2g (3F ) → 3 T 1g (F ), and the band at 1360 nm is assigned to the spin allowed transition 3 A 2g (3F ) → 3 T 2g (F ) [13,14]. The (T d) band at 682 nm can be attributed to transition 3 T 1 (F ) → 3 T 1 (P ) [15].…”

“…One of the favorable transition metal oxides is nickel oxide, which makes changes in the chemical composition of glass. If merged with the vitreous network of the glass, this combination leads to the gerenation of a homogeneous local ligand field Also, the nickel ions in 3d 8 electronic configuration are extremely stable in a glass network, even at room temperature [14][15][16][17]. Therefore, this work is devoted to the presentation of the structural modifications and the site symmetry around Ni 2+ ions, which can be well observed in the electron spin resonance (ESR) and VSM results.…”