Dislocations and particle size governed band gap and ferromagnetic ordering in Ni doped ZnO nanoparticles synthesized via co-precipitation
| Autor: | Ashok Rao, Sukriti Jain, Mukesh Saran, Anoop Kumar Mukhopadhyay, Kamakhya Prakash Misra, Arunava Agarwala, Nilanjan Halder, P.D. Babu, Saikat Chattopadhyay, Aga Shahee |
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| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
Materials science Dopant Rietveld refinement Band gap Process Chemistry and Technology Doping Analytical chemistry 02 engineering and technology 021001 nanoscience & nanotechnology Magnetic hysteresis 01 natural sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials 0103 physical sciences Materials Chemistry Ceramics and Composites Diamagnetism Crystallite 0210 nano-technology Wurtzite crystal structure |
| Zdroj: | Ceramics International. 45:23341-23354 |
| ISSN: | 0272-8842 |
| DOI: | 10.1016/j.ceramint.2019.08.034 |
| Popis: | To the best of our knowledge, the present work is the first ever report on how the Ni dopant concentration affects the dislocation density, band gap and most importantly the diamagnetic to ferromagnetic transition in ZnO nanoparticles (NPs), well known for multifunctional applications. For this purpose, undoped and Ni doped (1, 3, 5, and 7 at. wt.%) Wurtzite phase ZnO nanoparticles (NPs in size range 13–34 nm) are synthesized by sol-gel co-precipitation technique. As a function of the dopant concentrations (c), the polycrystalline NPs are characterized by XRD, Williamson-Hall plot, Rietveld refinement, UV–Vis spectroscopy, band-gap evaluation, dislocation density estimation, photoluminescence (PL) spectra, scanning electron microscopy (SEM),vibrating sample magnetometer (VSM) based magnetic moment (M) versus magnetic field (H) measurement, magnetic hysteresis measurement and resistivity (ρ) measurement. The results confirm that the dislocations density (δ(hkl)) along the (002) peak of XRD pattern governs the band gap energy (Eg) estimated from the corresponding Tauc’s plot. Further, both δ(hkl) and Eg exhibit interesting empirical dependencies on c. The PL spectra of all the NPs show the blue emission due to Zn interstitials. The SEM based photomicrographs prove the presence of the elongated spherical i.e, elliptical sub-structures forming a chain-like distribution in the microstructures which are sensitive to c. Further, the M-H loop reveal a transition from diamagnetic to ferromagnetic behavior as the presence of Ni in ZnO matrix enhances. A similar behavior is exhibited by ρ. These results are finally summarized in terms of structure-property correlations. The implications of the present materials in terms of possible futuristic applications are also discussed. |
| Databáze: | OpenAIRE |
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