• A BEN JAZIA KHARRAT

Articles written in Bulletin of Materials Science

• Prediction of magnetic and magnetocaloric properties in Pr$_{0.8−x}$Bi$_x$Sr$_{0.2}$MnO$_3$ ($x = 0$, 0.05 and 0.1) manganites

In this work, we have investigated the magnetic and magnetocaloric properties of Pr$_{0.8−x}$Bi$_x$Sr$_{0.2}$MnO$_3$ ($x = 0$, 0.05 and 0.1) polycrystalline manganites prepared by sol–gel route on the basis of a phenomenological model. Temperature dependence of magnetization indicates that all our samples exhibit a second order paramagnetic to ferromagnetic transition with a decrease in temperature. A correlation between experimental results and theoretical analysis based on a phenomenological model is investigated. The magnetic and magnetocaloric measurements are well simulated by this model. Under a magnetic applied field of 5 T, the theoretical absolute values of the maximum of magnetic entropy change $\Delta S_{\rm Max}$ are found to be equal to 5.33, 3.33 and 2.97 J kg$^{−1} K$^{−1}$for$x = 0$, 0.05 and 0.1 respectively. The relative cooling power and the specific heat capacity values are also estimated. The predicted results permit us to conclude that our compounds may be promising candidates for magnetic refrigeration at low temperatures. • Detailed investigation of the optical properties of the (C$_8$H$_{11}$BrN)$_3$BiCl$_6$compound by UV–visible measurements The UV–visible studies of the hybrid tris(4-bromo-N,N-dimethylanilinium) hexachlorobismuthate (III) compound [(C$_8$H$_{11}$BrN)$_3$BiCl$_6$], prepared by slow evaporation at room temperature, were investigated in detail from 200–2400 nm. The absorption peaks show the presence of a peak in the UV–C region around$\lambda_{\rm des}=254$nm which has the property of disinfecting water. The optical bandgap$E_{\rm g}$, determined by both absorbance and reflectance measurements, was estimated to be ($3.390 \pm 0.009$) and ($3.354 \pm 0.009$) eV, respectively. In addition, these measurements approve the direct behaviour of the allowed optical transitions. The low Eurbach energy (128 meV) confirms the high quality of the prepared sample. The dependence on the incident wavelength of the optical constants such as the extinction coefficient$k$and the refractive index$n$was discussed. The dispersion parameters$E_0$and$E_{\rm d}$of this compound were calculated on the basis of the Wemple–Didomenico model. Furthermore, the dielectric studies show that the dissipation factor$\tan \delta\$ has very low value. All the results demonstrate that this compound may be proposed as a good candidate for optical and optoelectronic applications.

• # Bulletin of Materials Science

Volume 44, 2021
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Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020

Physical Sciences 2020

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019