| Dielectric, electrical and optical properties of aluminosilicate ceramics synthesized by solid-state reaction route |
| Bijaylaxmi Biswal1, Dilip Kumar Mishra1, Jyoshnarani Mohapatra2, Satyanarayan Bhuyan3 |
1Department of Physics, Faculty of Engineering and Technology (ITER), Siksha ‘O’ Anusandhan Deemed to be University, Khandagiri Square, Bhubaneswar, Odisha 751030, India
2Department of Physics, College of Basic Science and Humanities, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha 751003, India
3Department of Electronics and Communication Engineering, Faculty of Engineering and Technology (ITER), Siksha ‘O’ Anusandhan Deemed to be University, Khandagiri Square, Bhubaneswar, Odisha 751030, India |
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Received: November 5, 2021; Revised: January 21, 2022 Accepted: February 12, 2022. Published online: March 4, 2022. |
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| ABSTRACT |
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The conventional high-temperature solid-state reaction technique is used to synthesize aluminosilicate ceramics of three different compositions (Al0.70Si0.30O, Al0.73Si0.27O, Al0.75Si0.25O). These aluminosilicate ceramics are systematically investigated by XRD, FTIR, SEM, dielectric, electrical, and UV–visible analysis. The polycrystalline ceramics are well synthesized at a sintering temperature of 1450 °C, confi rmed from XRD studies. The IR interferogram reveals the presence of mullite (3Al2O3 ·2SiO2)-type molecules in these aluminosilicate ceramics. The SEM images show the formation of homogeneous microstructures with appreciable density. The room temperature dielectric constant values for Al0.70Si0.30O, Al0.73Si0.27O, Al0.75Si0.25O ceramics are 1.5, 1.8, and 1.7 at 1 MHz frequency with dielectric loss values of 0.02, 0.04, and 0.06 respectively. The ac conductivity spectrum of these samples obeys the Arrhenius equation and the classical correlated barrier hopping model governs the conduction mechanism in these ceramics. Complex impedance analysis confirms the contribution of both grain and grain boundary towards transport processes in these ceramics. The UV–visible spectrum reveals that the synthesized ceramics, Al0.70Si0.30O, Al0.73Si0.27O, and Al0.75Si0.25O have a wide-band-gap of the order of 3.45 eV, 3.42 eV, and 3.39 eV respectively. These ceramics can be preferably used as electronic substrates, packaging material for high-frequency circuits, and infrared transmitting window materials. |
| Key words:
Mullite · Solid-state reaction method · Dielectric studies · Complex impedance · Optical band-gap |
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