Conduction mechanisms in lanthanum manganite nanofibers
| Autor: | Khizar Hayat, Syed Shaheen Shah, Yaseen Iqbal, Shahid Ali, Kamran Rasool |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
Materials science Scanning electron microscope Mechanical Engineering Analytical chemistry chemistry.chemical_element 02 engineering and technology Dielectric Activation energy 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences chemistry.chemical_compound Lanthanum manganite chemistry Mechanics of Materials Nanofiber Phase (matter) 0103 physical sciences Lanthanum General Materials Science Crystallite 0210 nano-technology |
| Zdroj: | Materials Science in Semiconductor Processing. 90:65-71 |
| ISSN: | 1369-8001 |
| Popis: | Lanthanum manganites are being constantly investigated for their interesting magnetic and transport properties. In this study, polycrystalline, single phase lanthanum manganite (LaMnO3) nanofibers were synthesized using an electrospinning technique, and characterized in terms of phase, microstructure, ac and dc electrical properties. X-ray diffraction and scanning electron microscopy revealed the formation of uniform composite nanofibers (average dia.∼ 600 nm) at 100 °C and polycrystalline single phase porous LaMnO3 nanofibers (average dia.∼ 400 nm) when calcined at 600 °C. Temperature dependent impedance and current-voltage (IV) characteristics of LaMnO3 nanofibers deposited on an interdigitated electrode type device, were investigated at temperatures ranging from 298 to 378 K. The observed decrease in the dielectric constant at high frequencies may be due to decrease in the contribution from dipolar polarization. Analysis of ac conductivity indicated thermally activated type conduction mechanism in these nanofibers which could be explained by a correlated barrier hopping (CBH) model. The observed decreasing trend in activation energy with increasing frequency also supported the CBH model. Furthermore, the analysis of log (J) vs. E0.5 curves at different temperatures showed a large difference of ~5.82 between the experimental and theoretical field lowering coefficient with an internal field enhancement factor of α2 = 33.91. This result excluded the possibility of Pool-Frenkel type conduction and the observed variation might be due to the presence of some localized electric fields. Further investigation of IV characteristics revealed that the ‘space-charge-limited current (SCLC) with traps’ may be the possible conduction mechanism. |
| Databáze: | OpenAIRE |
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