Premium
Dielectric Relaxation and Non‐Overlapping Small Polaron Tunneling Model Conduction Studies of Ag 2‐ x Na x ZnP 2 O 7 ( x = 0, 1, and 2) Materials
Author(s) -
Dhaou Mohamed Houcine,
Mallah Abdulrahman,
Alsawi Abdulrahman
Publication year - 2021
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.202100035
Subject(s) - polaron , dielectric , activation energy , relaxation (psychology) , thermal conduction , tetragonal crystal system , rietveld refinement , dielectric spectroscopy , quantum tunnelling , electrical resistivity and conductivity , condensed matter physics , materials science , powder diffraction , analytical chemistry (journal) , chemistry , crystallography , crystal structure , physics , electron , electrode , psychology , social psychology , optoelectronics , quantum mechanics , electrochemistry , chromatography , composite material
Abstract The Ag 2− x Na x ZnP 2 O 7 ( x = 0, 1, and 2) materials are prepared using the solid–solid method followed by heat treatment. The investigated samples are characterized by combining X‐ray powder diffraction and electrical impedance spectroscopy techniques. The Rietveld refinement of the X‐ray diffraction (XRD) pattern revealed that these Ag 2 ZnP 2 O 7 , AgNaZnP 2 O 7 , and Na 2 ZnP 2 O 7 compounds are indexed in the tetragonal system with the P4 2 / n space group. Their dielectric properties are measured in the frequency and temperature ranges of 200–10 7 Hz and 419–518 K, respectively. In these compounds, the dielectric relaxation can be described by a Cole–Cole model. The frequency dependence of the conductivity is interpreted in terms of Jonscher's law. For the three compounds, the activation energy for conduction has a different value compared to the activation energy for the relaxation process. This indicates that the conduction in the compound is not predicted by the simple hopping model. Then, the temperature dependence of the power‐law exponent(s) suggests that the non‐overlapping small polaron tunneling model is the dominant transport process in these materials. Moreover, the values of defect states N (EF) and the tunnel distance R W show the electrical performance of the Ag 2 ZnP 2 O 7 compound.