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Multān, Pakistan

Mahmood A.,Islamia University of Bahawalpur | Nadeem M.,Quaid-i-Azam University | Bashir B.,Islamia University of Bahawalpur | Shakir I.,King College | And 6 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2013

We report the structural, physical, dielectric and magnetic properties of of La1-xDyxNi1-yMnyO3 (x, y=0-1.0) nanoparticles synthesized by the micro-emulsion method. After characterization of the nanoparticles by thermogravimetric analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy and Fourier-transformed infrared spectroscopy, various electrical, dielectric and magnetic parameters were investigated. The diameter of the nanoparticles was found in the range of 30-60 nm as determined by XRD and SEM. Most of the samples exhibited the paramagnetic behavior apart from LaNiO 3, that exhibited the weak ferromagnetic behavior. The dc-electrical resistivity was also investigated at variable temperature (300-680 K). The maximum electrical resistivity (39.58×108 cm) was exhibited by La1-xDyxNi1-yMnyO3 (x, y=0), that was decreased to 0.45×108 cm as the Dy and Mn contents were increased. The dielectric parameters were measured at room temperature in the range of 100 Hz to 5.0 MHz. The maximum dielectric parameters (ε′=7.67×102, tanδ=2.96×103, ε″=2.27) were observed for La1-xDyxNi 1-yMnyO3 (x, y=0) nanoparticles. © 2013 Elsevier B.V.

Mumtaz S.,Bahuddin Zakaryia University | Warsi M.F.,Islamia University of Bahawalpur | Ashiq M.N.,Bahuddin Zakaryia University | Karamat N.,Bahuddin Zakaryia University | Shakir I.,King Saud University
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2015

Nanostructured Al2Zr2O7 and its vanadium Substituted derivatives Al2Zr2-xVxO7 (x=0, 0.25, 0.50, 0.75, 1.0) were prepared by the sol-gel auto-combustion method. The pyrochlore Al2Zr2-XVXO7 nanoparticles were characterized by energy dispersive X-ray spectroscopy (EDX), Fourier-transformed infrared (FTIR) spectroscopy, X-ray diffraction (XRD). The electrical resistivity was measured at varied temperature in the range of 300 to 675 K. The maximum electrical resistivity (119.88×108 ohm cm) was observed by Al2ZrVO7 (x=1.00) while Al2Zr2O7 (x=0.00) exhibited the minimum resistivity (56.85×108 ohm cm) at the same temperature. The dielectric behavior was measured at room temperature. All the dielectric parameters were found to decrease with increase in vanadium contents. The increase in electrical resistivity while decrease in dielectric behavior on substitution suggested that these materials may find potential applications in microwave devices as such devices required highly resistive materials. © 2015, National Institute of Optoelectronics. All rights reserved.

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