Electrical, dielectric and spectroscopic studies on MnO doped LiI–AgI–B2O3 glasses

Abstract

LiI-AgI-B 2 O 3 glasses doped with different concentrations of MnO (ranging from 0 to 0.8 mol%) were prepared. Electrical and dielectric properties have been studied over a wide frequency range of 10 À2 -10 6 Hz and in the temperature range from 173 to 523 K. The valence states of manganese ions and their coordination in the glass network have been investigated using optical absorption, luminescence, and ESR spectroscopy. The analysis of the spectroscopic results has indicated that the manganese ions exist in both Mn 2þ and Mn 3þ states and occupy octahedral and tetrahedral positions. With increasing MnO concentration there is a gradual increase in the tetrahedral occupancy of Mn 2þ ions at the expense of octahedral occupancy in the glass network. The results of dc conductivity have indicated that when T > h D /2, the small polaron hopping model is appropriate and the conduction is adiabatic in the nature. Further, the analysis of experimental data indicates that there is a mixed, ionic and electronic, conduction. It has been observed that the electrical conductivity decreases as the concentration of MnO increases suggesting the electronic conduction controlled by polaron hopping between manganese ions. In the low temperature region, up to 250 K, the ac conductivity is nearly temperature independent and varies linearly with frequency, which can be explained by the quantum mechanical tunneling (QMT) model. The dielectric properties have been analyzed in the framework of complex dielectric permittivity and complex electrical modulus formalisms. The evolution of the complex permittivity as a function of frequency and temperature has been investigated.

Paramagnetic behavior at room temperature of Zn1−xMnxTe nanocrystals grown in a phosphate glass matrix by the fusion method

“…Indeed, it has been reported that the g-factor of MnO doped glass samples increases with the MnO concentration [30]. This behavior, however, was not exhibited by the samples studied in this work.…”

Solubility limit of Mn2+ ions in Zn1−x Mn x Te nanocrystals grown within an ultraviolet-transparent glass template

“…1a) show that the intensity of these bands (350, 410 and 510 nm) and the PZABP: 0.8Mn sample (top spectrum) increases as x concentration increases. These bands (350, 410, and 510 nm) have also been observed in Mn:YAlO 3 crystals (Noginov and Loutts 1999), in LiI-AgI-B 2 O 3 (Wan et al 2014), and SrO-Al 2 O 3 -B 2 O 3 -SiO 2 glass systems doped with different levels of MnO (Milankovic et al 2012) and in MnO single crystals (Mochizuki et al 1992). The bands (350, 410, and 510 nm) are identified as 4 A 2 ( 4 F) ?…”

Influence of tin ions on AC conductivity and dielectric features of Li2O–PbO–P2O5 glass system

“…As a result charge carries are accumulated near the electrodes and cause large space near-surface charge polarization. The observed higher values of ε′(ω) at higher temperatures and at a lower frequency are obviously because of this polarization [19]. At a higher frequency, the charge carriers may not be able to rotate sufficiently rapidly and hence, their oscillation will begin to lay behind this field leading to a decrease of dielectric permittivity, ε′(ω).…”

“…2b variation of ε′(ω) with temperature for the same glass sample is presented. At higher frequency, ε′(ω) approaches to a constant value, ε′ ∞ (ω), which results in a rapid polarization processes occurring in the glasses under applied field [18,19]. With decreasing frequency dielectric constant reaches higher value, ε′ s (ω).…”