Synthesis and study of the structural and dielectric properties of La0.67Ca0.2Ba0.13Fe1−xMnxO3 ferrites (x = 0, 0.03 and 0.06)

Abstract

The La 0.67 Ca 0.2 Ba 0.13 Fe 1-x Mn x O 3 perovskite compounds with different manganese concentrations (x = 0.0, 0.03, 0.06) were synthesized by the autocombustion method and annealed at 700 °C. The X-ray diffraction (XRD) data indicated that all obtained compounds crystallize in the cubic structure with the Pm3m space group. The increase in the substitution rate has been found to lead to the decrease in the crystallite size value characterized by X-ray diffraction. The dielectric properties of these samples, using a complex impedance spectroscopy technique, were also performed as a function of frequency and temperature. A suitable equivalent electrical circuit was used to assess the contributions of electrode, grains, and grain boundaries in the complex impedance results. Activation energies were determined from different methods. Nyquist plots were consistent with three circuits in series, each one with a capacitance in parallel with a resistance. The conduction mechanism follows the NSPT model for the three samples at T \ 280 K, in which the rise in substitution rate increases the binding energy of carriers. Above 280 K, the appropriate model is the Correlated Barrier Hopping (CBH) for x = 0, while the overlapping large polaron tunneling (OLPT) process has been confirmed for both samples x = 0.03 and x = 0.06. Our compounds have high electrical properties, and good thermal and chemical stability. They are susceptible to many technological applications, such as gas sensors, capacitors, filters, resonators, new read heads, and solid oxide fuel cells.

Microstructural properties, dielectric behaviour, conduction mechanism, impedance, and electrical modulus of La0.65Ca0.25Sr0.1MnO3 manganite

“…Figure 11a illustrates the spectra of the real part M ′ versus frequency at different temperatures for the La 0.65 Ca 0.25 Sr 0.1 MnO 3 ceramic. From these curves, we can note that the M' has a lower value (approximately zero) in the low-frequency region, proposing that the electrode polarization makes a negligible contribution inside the La 0.65 Ca 0.25 Sr 0.1 MnO 3 ceramic [48]. On the other hand, one can observe that in the high-frequency region the M ′ values increase and had tended toward maximum.…”

“…10, we plot the logarithmic variation of Rg and Rgb as a function of 1000/T. The activation energy can be obtained using the Arrhenius law [48]:…”

Investigation of the structural, electrical, and dielectric properties of La0.5Sm0.2Sr0.3Mn1−xCrxO3 for electrical application

“…This behavior is similar to that observed in amorphous semiconductors and glasses. [33][34][35][36] Furthermore, based on the variation of the exponent n as a function of temperature we identify the predominant conduction process for our present compounds. Different models have been proposed to determine the conduction's nature, such as the Quantum Mechanical Tunneling (QMT), 37 the Correlated Barrier Hopping (CBH) model, 38 the Nonoverlapping Small Polaron Tunneling (NSPT) model, 39 and the Overlapping Large Polaron Tunneling (OLPT) model.…”

Study of the effect of the substitution of Fe by Ti on the microstructure and the physical properties of the perovskite system La0.67Ca0.2Ba0.13Fe1−xTixO3 with x = 0 and 0.03 at low temperatures

“… 6 The properties of these materials such as physical, photochemical, catalytic activity, and redox potential are variable depending on the replacement of positions A and B in these compounds. 7 The LaFeO 3 compound is a very attractive material due to its thermal stability, excellent catalytic activity, good oxidation power, super conductivity 8 high dielectric permittivity, chemical stability, low dielectric loss and high electrical resistivity. It exhibits an orthorhombic geometric structure with a Pbnm space group.…”