Structural, dielectric and transport properties of NaxFe1/2Mn1/2O2 (x=1 and 2/3)
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Date
13.06.2023Author
Faouzi MissaouiKawthar Trablsi
Krimi Moufida
Ayten Ateş
Abdelfattah Mahmoud
Frédéric Boschini
Abdallah Ben Rhaiem
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NaxFe1/2Mn1/2O2 (x = 1 and 2/3) layered oxides were prepared by an improved solid-state synthesis method. The XRD analysis confirmed the high purity of these samples. The Rietveld refinement of the crystalline structure illustrated that the prepared materials crystallize in a hexagonal system in the R3m space group with the P3 structure for x = 1 and in a rhombohedral system with the P63/mmc space group and P2 structure type for x = 2/3. The vibrational study undertaken using IR and Raman spectroscopy
techniques yielded the existence of an MO6 group. Their dielectric properties were determined in
frequency range 0.1–107 Hz for a temperature range 333–453 K. The permittivity results indicated the
presence of two types of polarization, namely dipolar polarization and space charge polarization. The
frequency dependence of the conductivity was interpreted in terms of Jonscher's law. The DC
conductivity followed the Arrhenius laws either at low or at high temperatures. The temperature
dependence of the power law exponent which corresponds to the grain (s2) suggested that the
conduction of the P3-NaFe1/2Mn1/2O2 compound is ascribed to the CBH model, while P2-Na2/3Fe1/2Mn1/2O2 can be attributed to the OLPT model.