1. Dielectric relaxation and conduction mechanism of NaMgPO4 compound
- Author
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L. Miladi, A. Oueslati, M. Ben Gzaiel, and M. Gargouri
- Subjects
Sodium-magnesium orthophosphate ,Raman ,phase transition ,NSPT model ,sodium-ion conductivity ,Electricity ,QC501-721 - Abstract
The polycrystalline NaMgPO4 ceramic, synthesized via a high-temperature solid-state reaction route, has been characterized by using different experimental procedures. The X-ray powder diffraction confirmed the phase formation of the synthesized compound in the orthorhombic phase. It assumed an olivine-type structure made up of corners linked between tetrahedral PO4 and octahedral NaO6 and MgO6 groups. Infrared and Raman spectroscopies confirmed the presence of PO[Formula: see text] groups. Local structure and chemical bonding between MgO6 octahedral and PO[Formula: see text] tetrahedral groups investigated by diffusion Raman is the feature in the phase transition at [Formula: see text] 693 K. The temperature dependences of the real [Formula: see text] and imaginary [Formula: see text] parts of dielectric permittivity show a distribution of relaxation times. From Nyquist plots, the presence of grain and grain boundary effect in the material is noticed. The impedance spectroscopy measurement showed a non-Debye-type process. From the impedance data, the determined grain resistance reduces with increment of temperature showing negative temperature coefficient of resistance (NTCR)-type nature of the material which also confirmed from conductivity analysis. The temperature dependence of [Formula: see text] reveals an Arrhenius-type behavior with two activation energies, 0.98 eV in region I and 0.67 eV in region II. Studied sample’s conduction is assured by Na[Formula: see text] ions’ hopping in tunnels and its mechanism was discussed.
- Published
- 2022
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