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Title: | Summerfield scaling model and electrical conductivity study for understanding transport mechanisms of a Cr3+ substituted ZnAl2O4 ceramic | Authors: | Elhamdi, I. Mselmi, F. Souissi, H. Kammoun, S. Dhahri, E. Sanguino, P. Costa, B. F. O. |
Issue Date: | 18-Jan-2023 | Publisher: | Royal Society of Chemistry | Project: | UIDB/04564/2020 UIDP/04564/2020 TAIL-UC facility funded under QREN-Mais Centro Project No. ICT_2009_02_012_1890 Tunisian Ministry of Higher Education and Scientic Research within the framework of the Tunisian- Portuguese cooperation (Project of University of Sfax- University of Aveiro) |
Serial title, monograph or event: | RSC Advances | Volume: | 13 | Issue: | 5 | Abstract: | Solid-state and sol-gel procedures were used to prepare ZnAl1.95Cr0.05O4 nanocrystal spinels. From the results obtained by X-ray diffraction (XRD) and transmission electron microscopy (TEM), it can be concluded that the samples prepared by sol-gel synthesis are better crystallized than the ones resulting from the solid-state method. Studies by spectroscopy of impedance were done in function of frequency (40-107 Hz) and temperature (540-680 K) in the sample prepared by sol-gel synthesis. The electrical conductivity spectra obey Jonscher's law and two models were observed studying the variation of the exponent 's' as a function of temperature, Correlated Barrier Hopping (CBH) and Non-overlapping Small Polaron Tunnelling (NSPT). The predominant conduction mechanism is bipolaron hopping. The scaling behavior of conductivity spectra was checked by Summerfield scaling laws. The time-temperature superposition principle (TTSP) points to a common transport mechanism working for the low and middle frequency ranges. The scaling mechanism fails in the high-frequency ranges suggesting that conduction dynamics, and the usual hopping distance of mobile species, have changed. The values obtained for the activation energy from the hopping frequency, conductivity σ dc, bulk resistance R gb, and relaxation (f max), in the temperature range of 540-680 K, are very close. A higher and negative temperature coefficient of resistivity (TCR coefficient) equal to -2.7% K-1 is found at 560 K. This result shows that our compound is suitable for uncooled infrared bolometric applications and infrared detectors. | URI: | https://hdl.handle.net/10316/114130 | DOI: | 10.1039/d2ra07701a | Rights: | openAccess |
Appears in Collections: | FCTUC Física - Artigos em Revistas Internacionais I&D CFis - Artigos em Revistas Internacionais FCTUC Eng.Mecânica - Artigos em Revistas Internacionais I&D CEMMPRE - Artigos em Revistas Internacionais |
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