Structural,magnetic and elastic properties of Mn0.3−xMgxCu0.2Zn0.5Fe3O4 nanoparticles

In this paper, Mn_0.3?xMg_xCu_0.2Zn_0.5Fe₃O₄ (x?=?0.00, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30) nanoparticles were prepared by the nitrate-citrate technique at low temperature. The structural, microstructural, magnetic and elastic properties of the samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, Transmission electron microscopy, field emission-scanning electron microscopy and vibrating-sample magnetometer at room temperature. Rietveld refinement of the XRD patterns indicated the formation of the single phase cubic spinel structure (space group Fd-3m) without any detectable impurity phase in all the samples that also was confirmed by FTIR studies. The lattice parameter is found to increase non-monotonically with an increase in Mg ion concentration. Also, the bond lengths and bond angles (A and B sites) of the studied ferrites were calculated by the refining of the XRD data. The values of the crystallite size decrease with increasing micro-strain (and conversely) and both of them reach extremum at x?=?0.15. The low remanence and coercivity values confirmed the formation of the superparamagnetic ferrites nanoparticles. The saturation magnetization of the samples gradually grows with Mg substitution and reach extremum at x?=?0.15. Variation of saturation magnetization with Mg content can be mainly attributed to change of cation distribution, and Yafet-Kittel angle occurred between magnetic moments on B-site in the samples. The values of Young's modulus, Debye temperature, bulk modulus, rigidity modulus of the samples were determined by the values of elastic constant and wave velocities obtained from the force constants. The improvement of the elastic properties of sample x?=?0.05 could be explained regarding the smaller values of the lattice parameter (a), the bond length and angle and the smaller crystallite size.     

Structural,magnetic and catalytic properties of La2-xBaxCuO4 (0 ≤ x ≤ 0.5) perovskite nanoparticles

Barium doped La₂CuO₄ perovskite nanoparticles were synthesized via microwave assisted combustion method. The effects of Ba²⁺ doping on structural, optical, magnetic and catalytic activity of La₂CuO₄ have been studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) and vibrating sample magnetometer (VSM) techniques. The XRD patterns of pure La₂CuO₄ and La_1.9Ba_0.1CuO₄ confirmed the formation of perovskite structure without impurities. However, with increasing Ba²⁺ content in the range 0.2–0.5, phase transformation from orthorhombic to tetragonal structure, occurred. The average crystallite size of orthorhombic and tetragonal phases were in the range 45.2–52.2?nm and 0.5–41?nm, respectively. The appearance of FT-IR bands at around 685 and 517?cm^?1 were correlated to the La-O and Cu-O stretching modes of orthorhombic La₂CuO₄ phase. The direct band gap estimated using Kubelka–Munk (K–M) method decreased with the increase in Ba²⁺ content (1.88–1.64?eV), due to the formation of sub-bands in the energy band gap. Magnetic measurements of doped La₂CuO₄ samples showed either para- or ferro-/para- magnetic behaviour at room temperature. The catalytic activity (oxidation) tests carried out in a batch reactor operating under atmospheric conditions indicated that the prepared catalysts, in particular (La_1.7Ba_0.3CuO₄), showed excellent catalytic activity.     

Synthesis,structural, electrical and magnetic properties of Bi2Fe4-xGaxO9 (0 ≤ x ≤ 1.6)

We investigate the electrical and magnetic properties of the Bi₂Fe_4-xGa_xO₉ (0?≤?x?≤?1.6) polycrystalline samples synthesized via solid-state reaction technique. Magnetic susceptibility measurements reveal that lightly doped samples (x?<?0.8) undergo successive transitions, from high-temperature paramagnetic to antiferromagnetic phase followed by a low-temperature spin-glass state while the samples with heavy doping (x?>?0.8) demonstrate paramagnetic to spin-glass (SG) transition. The variation of irreversible temperature obtained from zero field cooling (ZFC) and field cooling (FC) susceptibilities versus measured magnetic field and low-temperature magnetic hysteresis (M-H) loops support the existence of spin-glass phase. The dielectric constant (?_r) of Bi₂Fe_4-xGa_xO₉ with Ga-dilution reveals a weak-temperature sensitivity in high-temperature range (300?K?≤?T?≤?550?K), which is advantageous for high temperature capacitor applications and electronic devices.     

Structural and magnetic evaluation of substituted NiZnFe2O4 particles synthesized by conventional sol–gel method

The aim of this study is to evaluate the structural and magnetic properties of Ni–Zn doped ferrite with trivalent Al³⁺ and Cr³⁺ cations substitution in Ni_0.6Zn_0.4Fe_2−xCr_x/2Al_x/2O₄ (x=0, 0.1, 0.2, 0.3, 0.4 and 0.5) synthesized by employing conventional sol–gel method. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), Mössbauer spectroscopy (MS) and vibrating sample magnetometer (VSM) analysis were carried out in order to characterize the structural and magnetic properties of particles. The XRD results confirmed the formation of single phase of spinel ferrite particles for a whole series of samples. The results of FTIR analysis indicated that the functional groups of Ni–Zn spinel ferrite were formed during the sol–gel process. Furthermore, FE-SEM micrographs revealed that the distribution of particles size is narrow. According to Mössbauer spectra,the doped cations are replaced in iron site occupancy of octahedral sites. It was found that with an increase in substitution contents magnetization decreased due to occupation of Al and Cr cations at low level substitutions in octahedral sites.     

Crystal structure,Raman spectra and microwave dielectric properties of Li2Mg3Ti1-x(Mg1/3Nb2/3)xO6 (0 ≤x ≤ 0.25) ceramics

Li₂Mg₃Ti_1-X(Mg_1/3Nb_2/3)_XO₆ (0?≤x?≤?0.25) ceramics were prepared by a conventional solid-state reaction process. Their crystal structures, sintering characteristics, Raman spectra and microwave dielectric properties were then investigated. XRD patterns of the sintered samples indicated that all compositions showed a single phase and the rock-salt structure. As the (Mg_1/3Nb_2/3)⁴⁺ contents increase, the variations of ε_r values showed a downward trend, which could be explained by the changes of polarizabilities and the shift of Raman vibration modes. Q·f values initially increased to a maximum value and then decreased with increasing of x values. In addition, τ_f values decreased almost linearly with the x values, which significantly correlated with the thermal expansion coefficient. Excellent combined microwave dielectric properties with ε_r =?14.79, Q·f?=?204,900?GHz and τ_f =??18.43?ppm/°C were obtained for Li₂Mg₃Ti_.95(Mg_1/3Nb_2/3)_.05O₆ ceramic sintered at 1550?°C.     

Structural and magnetic properties of Pr–Ni substituted Ca0.5Ba0.5Fe12O19 hexa-ferrite nanoparticles

Effect of Pr–Ni substitution on structural and magnetic properties of Ca_0.5Ba_0.5−xPr_xNi_yFe_12−yO₁₉ (x=0.00–0.10 and y=0.00–1.00) prepared by the sol–gel auto combustion method were investigated. The XRD analysis confirmed the single phase M-type hexa-ferrite structure. The lattice parameters were found to increase as Pr–Ni content increases, which is attributed to the ionic size of the implicated cations. The Pr–Ni seems to be completely soluble in the lattice. Transmission electron microscopy reveals that the grain size decreases with increase of Pr–Ni substitution. The coercivity and remanent magnetization ranges from 1511 to 1925 (Oe) and 21.4 to 26.5 (emu/g), respectively. The coercivity values of all the samples fall in the range of M-type hexa-ferrites.     

Ni1-xZnxFe2O4铁氧体的制备及其性能研究

通过化学共沉淀法制备了颗粒较细、粒度分布较均匀、团聚较少的Ni1-xZnxFe2O4前驱体。通过TG-DSC分析、XRD测量、激光粒度分析和形貌观察确定了Ni1-xZnxFe2O4前驱体的优化煅烧温度。以活性Ni1-xZnxFe2O4前驱体为原料,通过固相反应法制备Ni1-xZnxFe2O4陶瓷。不同温度烧结的、不同组成的Ni1-xZnxFe2O4陶瓷均呈现纯尖晶石结构。Zn2+含量、烧结温度对Ni1-xZnxFe2O4陶瓷的结构、密度、物理性能产生重要影响。在相同的烧结温度下,随着Zn2+含量的增加,Ni1-xZnxFe2O4陶瓷的密度、方块电阻、饱和磁化强度呈现增大的趋势。随着烧结温度的升高,Ni1-xZnxFe2O4陶瓷的密度、方块电阻、饱和磁化强度明显增大。     

Structural and magnetic properties of Li2O–Fe2O3 ceramic nanostructures

xLi₂O–(1−x)α-Fe₂O₃ (x=0.1, 0.3, 0.5, and 0.7) nanoparticle systems were successfully synthesized by mechanochemical activation of Li₂O and α-Fe₂O₃ mixtures for 0–12 h of ball milling time. The study aims at exploring the formation of magnetic oxide semiconductors at the nanoscale, which is of crucial importance for catalysis, sensing and electrochemical applications. X-ray powder diffraction (XRD), Mössbauer spectroscopy and magnetic measurements were used to study the phase evolution of xLi₂O–(1−x)α-Fe₂O₃ nanoparticle systems under the mechanochemical activation process. Rietveld refinement of the XRD patterns yielded the values of the particle size as function of composition and milling times and indicated the presence of Li-substituted hematite and tetra lithium iron oxide LiFeO₂, along with the formation of multiple phases for large x values and long milling times. The Mössbauer studies showed that the spectrum of the mechanochemically activated composites evolved from a sextet for hematite to sextets and a doublet upon duration of the milling process with lithium oxide. Magnetic measurements recorded at 5 K to room temperature (RT) in an applied magnetic field of 50,000 Oe showed that the magnetization of the milled samples is larger at low temperatures than at RT and increases with decreasing particle size. Zero field cooling measurements made possible the determination of the blocking temperatures of the specimens as function of ball milling time and evidenced the occurrence of superparamagnetism in the studied samples. This result correlates well with the observed presence of a quadrupole-split doublet in the Mössbauer spectra.     

Structural,magnetic, electrical and dielectric properties of MnxNi1−xFe2O4 spinel nanoferrites prepared by PEG assisted hydrothermal method

Mn_xNi_1?xFe₂O₄ (x=0.2, 0.4, 0.6) nanoparticles were synthesized by a polyethylene glycol (PEG)-assisted hydrothermal route. We present a systematic investigation on the structural, magnetic, electrical and dielectric properties of the products by using XRD, FT-IR, SEM, TGA, VSM and dielectric spectroscopy, respectively. Single phased cubic spinel structure was confirmed for all samples and the average crystallite size of the products was estimated using Line profile fitting and ranges between 6.5 and 11 nm. The nanoparticles have ferromagnetic nature with small coercivity. The samples showed semiconducting behavior which is revealed from temperature dependent conductivity measurements. Temperature and frequency dependent dielectric property; dielectric permittivity (ε) and ac conductivity (σ_AC) studies for the samples indicated that the dielectric dispersion curve for all samples showed usual dielectric dispersion confirming the thermally activated relaxation typical for Debye-like relaxation referring to it as the Maxwell–Wagner relaxation for the interfacial polarization of homogeneous double structure. The particle size, saturation magnetization, coercive field, conductivity and dielectric constant of the samples are strictly temperature dependent and increased with Mn concentration.     

Structural,magnetic and dielectric properties of Co-Zr substituted M-type calcium hexagonal ferrite nanoparticles in the presence of α-Fe2O3 phase

Polycrystalline nanoparticles of M-type Ca(ZrCo)_xFe_12?2xO₁₉ (0.0?≤?x?≤?1.0) hexaferrites were prepared using a simple heat treatment method at a low heating temperature of 650?°C. Effect of cobalt-zirconium substitution on the structural, microstructural, magnetic and dielectric properties was investigated. XRD analysis indicates that all the samples possess a hexagonal structure with anti-ferromagnetic α-Fe₂O₃ phase. The values of lattice parameters and cell volume found to be increased with increasing the cobalt-zirconium substitution along with the amount of α-Fe₂O₃ phase. Crystal symmetry has not affected by Zr–Co substitution in prepared calcium hexaferrite samples but the position of diffraction peak [108] is found to shift towards a lower angle as an increase in the substitution of Zr–Co. The crystallite size found to vary between 12 and 17?nm. SEM images show agglomerated grains and surface morphology has changed with Zr–Co substitution. EDX analysis of typical samples revealed the presence of Ca, Fe, Co, Zr. The magnetic analysis revealed the formation of multi-domain structure. Room temperature Mössbauer spectra of prepared samples show that all five sextets are merged together with a paramagnetic doublet and it confirmed that the size of particles is very small in the nano range. Single and double semicircle arcs were observed in Cole-Cole plots, due to the contributions of grain and grain boundaries resistance.     

Dielectric,ferroelectric, magnetic and magnetoelectric properties of 0.1Ni0.8Zn0.2Fe2O4–0.9Pb1−3x/2SmxZr0.65Ti0.35O3 magnetoelectric composites

Composites having general formula 0.1Ni_0.8Zn_0.2Fe₂O₄–0.9Pb_1−3x/2Sm_xZr_0.65Ti_0.35O₃ with x=0, 0.01, 0.02 and 0.03 were synthesized by a conventional solid state reaction route. X-ray diffraction analysis was carried out to confirm the coexistence of individual phases and microstructural study was done by using a scanning electron microscope. Dielectric properties were studied as a function of temperature and frequency. To study ferroelectric and magnetic ordering in composite samples, P–E and M–H hysteresis loops were recorded respectively. Maximum magnetoelectric coupling coefficient of 22.5 mV/cm Oe was observed for sample with x=0.03. A significant improvement in dielectric, ferroelectric, piezoelectric and magnetoelectric properties was observed for Sm substitution.     

Microstructure and magnetic properties of Ni0·75Zn0·25Fe2O4 ferrite prepared using an electric current-assisted sintering method

Using a Ni_0·75Zn_0·25Fe₂O₄ nanopowder synthesized by means of a hydrothermal method as a raw material, polycrystalline nickel zinc (NiZn) ferrite ceramics composed of sub-micron grains were successfully prepared via an electric current-assisted sintering method. Temperatures ranging from 800 °C to 950 °C and a dwell time of 20 min were employed. The phase composition and microstructure of the samples were characterized via X-ray diffraction and scanning electron microscopy, respectively. Moreover, the magnetic properties of the samples were investigated using a vibrating sample magnetometer and a ferromagnetic resonance system. The results revealed that each sintered sample was mainly composed of a spinel phase. With increasing sintering temperature, the specific saturation magnetization increased from 71.85 emu/g to 74.58 emu/g, owing mainly to the increase in the relative density and the average grain size of the NiZn ferrites. The coercivity and ferromagnetic resonance linewidth of the ferrite ceramics decreased monotonically with increasing sintering temperature, owing mainly to the magnetostriction coefficient, saturation magnetization, and porosity of the sintered ferrites.     

Temperature dependence of the dynamic electrical properties of Cu1+xMn1-xO2 (x = 0 and 0.06) crednerite materials

Polycrystalline samples of Cu_1+xMn_1-xO₂ (x?=?0 and 0.06) have been obtained by solid state reaction in silica tubes. Measurements of complex impedance (Z?=?Z′?+?iZ′′) at various temperatures T, between 30 °C and 120 °C and over the frequency range 100?Hz–2?MHz were performed. The frequency dependence of Z′′(f) exhibits a maximum which moves towards higher frequencies by increasing the temperature, proving thus the hopping of the charge carriers between the localized states is the dominant mechanism for the electrical conduction in the investigated samples. The barrier energy values were: 0.287?eV for CuMnO₂ and 0.208?eV for Cu_1.06Mn_0.94O₂.The conductivity spectrum, σ(f) follows the Jonscher universal law at each constant temperature. Based on the temperature and frequency dependencies of the electrical conductivity and using the variable-range-hopping (VRH) model, the frequency and temperature dependencies of the density of localized states near the Fermi level, N(E_F), the hopping distance, R and the hopping energy, W were computed. The results show that at constant frequency, N(E_F) does not depend on temperature for both samples. At constant temperature and frequencies up to 30?kHz, increasing the concentration of Cu ions leads to the decrease of R and W, whilst at high frequencies (over 100?kHz), R and W increase with the increase in the concentration of Cu ions.     

Effects of Ti-substitution on the crystal structures,micro-structures and microwave dielectric properties of Li2Mg3Zr1-xTixO6 (0 ≤ x ≤ 1) ceramics

Li₂Mg₃Zr_1?xTi_xO₆ (x = 0, 0.2, 0.4, 0.6, 0.8, 1) ceramics were prepared via a solid-state reaction method. Crystal structures, sintering behaviors, micro-structures and microwave dielectric properties of Li₂Mg₃Zr_1?xTi_xO₆ (0 ≤ x ≤ 1) ceramics were investigated by XRD, SEM and chemical bond theory. XRD results showed that a single phase with the rock-salt structure was formed in all ranges. On the basis of the Rietveld refinement and chemical bond theory, several intrinsic parameters were calculated and connections between intrinsic parameters and microwave dielectric properties were investigated. The substitutions of Ti⁴⁺ for Zr⁴⁺ obviously increased the relative density and improved the quality factors. Variations of ε_r could be explained by changes of the polarizability. Q·f values showed the similar trend with the packing fractions, average bond valences and lattice energy of Zr–O bonds. τ_? values significantly correlated with the bond energy of Zr–O bonds.     

High dielectric and microwave absorption properties of ultra-thin 1-xSrTiO3-δ − xSrAl12O19 films

To reduce the thickness of the microwave absorbing materials, we have prepared 1-xSrTiO_3-δ?xSrAl₁₂O₁₉ ceramics by hot?pressing sintering in the vacuum. The microstructure, dielectric, thermogravimetric analysis and microwave absorbing properties of 1-xSrTiO_3-δ?xSrAl₁₂O₁₉ were systematically investigated and discussed. The 0.95SrTiO_3-δ??0.05SrAl₁₂O₁₉ has high permittivity, the real part is from 1662.2 to 704.9 and the imaginary part is from 208.6 to 12. The absorption bandwidth (reflection loss ≤?5?dB) of 0.95SrTiO_3-δ??0.05SrAl₁₂O₁₉ can cover 8.6???12.4?GHz and its thickness is only 0.232?mm which is much thinner than these recently reported by other researchers. For 0.942SrTiO_3-δ??0.058SrAl₁₂O₁₉, the peak value of reflection loss is up to ??58.5?dB with a thickness of 0.75?mm. The 1-xSrTiO_3-δ?xSrAl₁₂O₁₉ films could be excellent candidates for highly efficient and ultra?thin microwave absorbing materials.     

The optimal synthesis condition by sol–gel method and electrical properties of Mn1.5−xCo1.5NixO4 ceramics

A series of Mn_1.5−xCo_1.5Ni_xO₄ (0≤x≤1.2) negative temperature coefficient materials was synthesized by the sol–gel method. The optimal pH of reaction solutions was obtained by theoretical calculation. XRD and X-ray intensity ratios (I₂₂₀/I₄₄₀) and (I₄₄₀/I₄₂₂) studies showed that as-sintered ceramics are single spinel structures with different cation distributions. The Ni²⁺ ions not only enter B-site but also occupy A-site. Electrical studies showed that with increasing Ni content, the resistivity decreased from 909.229 Ω cm to 221.873 Ω cm initially in the range of x≤0.5 and then increased to 726.933 Ω cm when x=1.2, whereas the B value decreased from 4427 K to 2134 K. In addition, different sintering temperature ceramics were investigated. A higher sintering temperature results in lower resistivity and B value at same Ni content. The Mn_1.0Co_1.5Ni_0.5O₄ material showed much improved electrical stability at 125 °C for 1000 h. The rate of change (ΔR/R) is 0.2%.     

Magneto-electric properties of xNi0.7Zn0.3Fe2O4 – (1-x)BaTiO3 multiferroic composites

Di-phase ceramic composites, with general formula xNi_0.7Zn_0.3Fe₂O₄ – (1-x)BaTiO₃(x = 0.9, 0.7, 0.5, 0.3, 0.1), were prepared by a mixing method. X-ray analysis, for powder and ceramics, indicated the formation of ferrite and barium titanate phases without the presence of the impurities. SEM analysis indicated that the composite morphology contained two types of grains, polygonal and rounded. Homogeneous microstructure and the smallest grain size were obtained in ceramics with 70% of barium titanate. The electrical properties of these materials were investigated using impedance spectroscopy, dielectric and ferroelectric measurements. The NZF-BT(30-70) composite has shown better electrical properties in comparison to other investigated ceramics, confirmed by dielectric and ferroelectric data analysis. Saturation magnetization and coercive field decreased with the increase of the content of ferroelectric phase.     

Weakly agglomerated α-Al2O3 nanopowders prepared by a novel spray precipitation method

In this paper, weakly agglomerated and well dispersed α-Al₂O₃ powders were synthesized by a novel spray precipitation method. It was demonstrated that the as-prepared powders exhibited better dispersity than powders from conventional precipitation due to the increased phase contact and reaction area during the precipitation process. The effects of different titration ways, calcination temperature and holding time on the morphology, phase composition and sintering behaviour of Al₂O₃ powders were systematically investigated. Weakly agglomerated and well crystallized α-Al₂O₃ powders were obtained when the as-prepared precursors were calcined at 1150?°C for 2?h in air. The average particle size of α-Al₂O₃ powders with higher sintering activity was approximately 68.6?nm, and the specific surface area was above 22.4?m² g^?1.     

Comparative study of magnetoelectric composite system Ba0.95Sr0.05TiO3–Ni0.8Co0.2Fe2O4 with ferrite prepared by different methods

In this paper, effect of addition of Ni_0.8Co_0.2Fe₂O₄ (NCF), prepared by three different methods namely solid state reaction method, sol–gel and co-precipitation, has been studied on microstructural, magnetic, dielectric, ferroelectric and magnetoelectric properties of multiferroic composite system 0.95 Ba_0.95Sr_0.05TiO₃–0.05 Ni_0.8Co_0.2Fe₂O₄. Ba_0.95Sr_0.05TiO₃ (BST) has been prepared by solid state reaction method. Titular representation of NCF samples prepared by sol–gel, co-precipitation, solid state reaction method is N–SG, N–CP, N–SS respectively and that of corresponding magnetoelectric composite is C–SG, C–CP, C–SS. X–ray diffraction analysis of the composite samples (C–SG, C–SS, C–CP) indicated the presence of both NCF and BST phases. Rietveld analysis of XRD pattern further confirmed the proper phase formation in the composite samples. Sol–gel and co-precipitation processes result in finer NCF particles as confirmed by Transmission electron microscopy (TEM). Sample N–SG possesses uniform particle size and shape. Magnetization versus magnetic field (M–H) loops of samples C–SS and C–CP possess respectively highest value of remanant magnetization and magnetic coercive field. Dielectric properties of BST, NCF and composite samples have been measured in the frequency range of 20 Hz–1 MHz and temperature range of 50–170 °C. The composite sample C–CP results in highest value of dielectric constant in comparison to samples C–SS and C–SG. Polarization versus electric field (P – E) measurements pointed that composite sample C–SG possesses highest value of remanant and saturation polarization and C–SS possesses lowest value of coercive electric field. The composite sample C–SS possesses highest value of magnetoelectric coefficient.     

Sol-gel synthesized and microwave heated Pb0.8-yLayCo0.2TiO3 (y = 0.2–0.8) nanoparticles: Structural,morphological and dielectric properties

In this work, the Pb_0.8-yLa_yCo_0.2TiO₃ (y?=?0.2–0.8) (PLCT) nanoparticles were prepared by sol-gel method and further subjected to microwave heating. The formed tetragonal reflection planes of PLCT samples were on par with PbTiO₃ (PT) and lanthanum cobalt titanate (LCT) tetragonal phases. Especially, for y?=?0.2–0.4, PLCT attained the PT structure while for y?=?0.6–0.8, PLCT acquired the LCT structure. That is, the structural transformation occurred from tetragonal PT to tetragonal LCT phases at higher La-contents. The high resolution transmission electron microscope (HRTEM) and field emission scanning electron microscopes (FESEM) showed complete formation of nanofibers at y?=?0.8 which may reveal drug delivery system applications. The Fourier transform infrared spectra (FTIR) were recorded in order to find the presence of metal oxide bonds. The dielectric properties evidenced that the transition temperatures (T_c) were found to be increasing from 713 to 783?K with increase of y-value. Furthermore, the temperature and frequency dependence of dielectric constant (ε′), dielectric loss (ε′′), ac-electrical conductivity (σ_ac), real (M′) and imaginary (M′′) parts of complex dielectric modulus (M*) was described. The Power law was used to fit the logσ_ac versus logω plots in order to determine the dc-conductivity (σ_dc) and exponent (n) values of the samples at room temperature (RT). Later on, the Arrhenius plots (lnσ_ac versus T^?1 plots) were drawn to find the activation energies. The results expressed the existence of two activation energies at low and high temperature regions due to slope change before and after T_c.