Structural,electrical and magneto-electric characteristics of complex multiferroic perovskite Bi<Subscript>0.5</Subscript>Pb<Subscript>0.5</Subscript>Fe<Subscript>0.5</Subscript>Ce<Subscript>0.5</Subscript>O<Subscript>3</Subscript>

The polycrystalline sample of bismuth based-complex multiferroic of a composition Bi_0.5Pb_0.5Fe_0.5Ce_0.5O₃ was prepared by a high-temperature solid-state reaction technique (calcinations temperature = 900 °C, sintering temperature = 960 °C, time = 4 h). Preliminary structural analysis using XRD data exhibits the formation of a single-phase compound. Studies of surface morphology of the ceramic sample of the compound, recorded at room temperature using a scanning electron microscope, show uniform distribution of grains of different size with few voids. Detailed studies of dielectric properties (ε_r, tan δ) supported the existence of multiferroic properties in the above complex system. The analysis of impedance parameters, recorded in a wide frequency (1 kHz–1 MHz) and temperature (room temperature to 450 °C) range of the material provide better understanding of (a) role of grains and grain boundaries in resistive and capacitative characteristics, (c) structure-properties relationship and (b) type of relaxation process occurred in the material. Study of temperature dependence of dc conductivity of the compound shows the existence of negative temperature coefficient of resistance in it. The nature of variation of ac conductivity with temperature of the material follows the Josher’s universal power law. Study of magneto-electric characteristics of the sample at room temperature has provided many useful and new data on magneto-electric coupling coefficient of different orders.     

Structural and electrical properties of lead reduced lanthanum modified BiFeO<Subscript>3</Subscript>–PbTiO<Subscript>3</Subscript> solid solution

Lanthanum modified binary electronic systems of BiFeO₃ (BFO) and PbTiO₃ (PT) in different molar ratios with reduced lead (Pb) content have been synthesized by using a high-temperature solid-state reaction technique. Detailed studies of structural, morphological and electrical properties of the prepared solid solutions [(Pb_1?xBi_0.5xLa_0.5x)(Fe_xTi_1?x)O₃ with x = 0.1, 0.3, 0.5 and 0.7] have provided some interesting findings on structure-properties relationship. An abrupt change is observed in the structure of the solid solution from tetragonal to rhombohedral with the increase of La concentration. The micro-structural analysis reveals that the grain size of the system reduces on increasing La concentration of the prepared electronic system. The reduction of Pb concentration not only advances the dielectric response of lanthanum modified BiFeO₃–PbTiO₃ electronic material but also suppresses the toxic behavior of the material. For higher concentration of La, the remnant polarization is observed to be minimum. The impedance studies exhibit the presence of grain and grain boundary effects, and existence of a negative temperature coefficient of resistance (NTCR) in the material. The ac conductivity increases with increase in frequency in the low-temperature region for all the materials. It is observed that the prepared electronic materials obey the non-exponential type of conductivity relaxation.     

Effects of addition of BiFeO<Subscript>3</Subscript> on phase transition and dielectric properties of BaTiO<Subscript>3</Subscript> ceramics

Samples of xBiFeO₃–(1 − x)BaTiO₃ (x = 0, 0.02, 0.04, 0.06, 0.07 and 0.08) were synthesized by solid state reaction technique and sintered in air in the temperature range 1,220–1,280 °C for 4 h. X-ray diffraction data showed that 2–8 mol% BiFeO₃ can dissolve into the lattice of BaTiO₃ and form single perovskite phase. The crystal structure changes from tetragonal to cubic phase at room temperature when 8 mol% of BiFeO₃ was added into BaTiO₃. Scanning electron microscope images indicated that the ceramics have compact and uniform microstructures, and the grain size of the ceramics decreases with the increase of BiFeO₃ content. Dielectric constants were measured as functions of temperatures (25–200 °C). With rising addition of BiFeO₃, the Curie temperature decreases. For the sample with x = 0.08, the phase transition occurred below room temperature. The boundary between tetragonal and cubic phase of the BiFeO₃–BaTiO₃ system at room temperature locates at a composition between 7 and 8 mol% of BiFeO₃. The diffusivity parameter γ for compositions x = 0.02 and x = 0.07 is 1.21 and 1.29, respectively. The relaxor-like behaviour is enhanced by the BiFeO₃ addition.     

Preparation and microwave absorption properties of BiFeO<Subscript>3</Subscript> and BiFeO<Subscript>3</Subscript>/PANI composites

BiFeO₃(BFO) particle was successfully synthesized by normal citric acid sol–gel method and the size of BiFeO₃ particle is about 200 nm. BiFeO₃/polyaniline (PANI) composites with the different weight ratio were synthesized by in situ emulsion polymerization. The citric acid doped PANI is fibrous and form a loose structure outside the BFO particle. With the increasing of PANI, the conductivity value of composites are increasing to 9.34?×?10^?2 S/cm. Moreover, the permittivity also enhance with the increasing of conductivity, which contribute to the improvement of dielectric loss. Microwave absorbing properties were investigated with a vector network analyzer in 1–18 GHz. The minimum reflection loss (RL) value is about ?40.2 dB at 8.3 GHz when the thickness is 3.5 mm, and the maximum bandwidth less than ?10 dB is 3.5 GHz (from 13.5 to 18 GHz) at the thickness of 2 mm. 3 mm millimeter-wave-attenuation properties were also tested, and the maximum attenuation value of BFO/PANI composites reach 15.71 dB. The composites can dissipate microwave energy into heat effectively by dielectric relaxation because of the suitable conductivity. The interface scattering and multiple reflections also play a important role because of the increasing of a loose structure. The BFO/PANI composite can be taken as a promising lightweight and multiband microwave absorber.     

The synergetic electromagnetic properties and enhanced microwave absorption of BiFeO<Subscript>3</Subscript>/BaFe<Subscript>7</Subscript>(MnTi)<Subscript>2.5</Subscript>O<Subscript>19</Subscript> composite

The effective microwave absorption materials could contribute to alleviating the electromagnetic wave pollution. However, conventional microwave absorption materials usually suffer from insufficient absorption intensity and the narrow effective absorption bandwidth. Herein, BiFeO₃/BaFe₇(MnTi)_2.5O₁₉ composites are proposed to address these issues through offering synergetic electromagnetic properties and proper electromagnetic properties. BiFeO₃ combined with BaFe₇(MnTi)_2.5O₁₉ exhibits dielectric multiple relaxation behaviors, strong ferromagnetic resonance and electromagnetic matching, ensuring increased multi-band microwave absorption. Accordingly, the minimum reflection loss (RL) of the composite with volume ratio of 1.5:1 reaches ??48 dB, and the bandwidth less than ??10 dB covers multi-frequencies at C, X and Ku band. These results suggest that BiFeO₃/BaFe₇(MnTi)_2.5O₁₉ composite could be a promising microwave absorption material in imaging, healthcare, information safety and military fields.     

Chelation and calcination promoted preparation of perovskite-structured BiFeO<Subscript>3</Subscript> nanoparticles: a novel magnetic catalyst for the synthesis of dihydro-2-oxypyrroles

Perovskite-structured Bismuth ferrite (BiFeO₃) nanoparticles as a novel heterogeneous catalyst were designed by an auto combustion route using a different chelating agent and calcination temperature. The effect of different chelating agents like disaccharide (sucrose), α-hydroxy acid (citric acid, tartaric acid), amide (urea) and calcination (150–750 °C) temperature on structure and the catalytic performance of BiFeO₃ have been analyzed. The catalytic performance of BiFeO₃ has been increased by modifying its synthesis with the addition of suitable organic compound and calcination. BiFeO₃ synthesized without the use of chelating agent gave very poor yield, i.e., 36.89%. The augmented effect of the chelating agent on the catalytic performance of BiFeO₃ was obtained in the order of blank < tartaric acid < sucrose < urea < citric acid, whereas the enhancing effect of calcination temperature in the order 150 °C < 450 °C < 550 °C < 650 °C > 750 °C. The calcination temperature results in augmentation in yield of approximately 30% with model reaction on increasing temperature from 150 to 650 °C. Different calcination temperatures (150–750 °C) have been employed to obtain single phase BiFeO₃ nanoparticles. All synthesized BiFeO₃ nanoparticles were fully characterized by FT-IR; XRD; VSM; BET; TGA; XPS and Raman spectroscopy. For the very first time ever we have used them as a recyclable magnetic nanocatalyst in the formation of highly substituted dihydro-2-oxypyrrole by using one-pot, three-component reaction of DMAD, aniline and formaldehyde in methanol at room temperature with 63–88% yield. All the synthesized oxypyrroles have been characterized by various spectroscopic techniques.     

Effect of Li and Bi co-substituted on structural and physical properties of BaTiO<Subscript>3</Subscript> ceramics

Polycrystalline samples of Li and Bi co-substituted BaTiO₃ were synthesized using microwave assisted heating of the starting materials. This synthesis process extraordinarily reduced the processing time to 40 min, which includes heating and the dwell durations. The room temperature powder X-ray diffraction patterns reveals that the obtained compounds were of pure BaTiO₃ phase (BTO). The structural, morphological and dielectric behaviour of these compositions were studied. Improved dielectric properties have been observed with the substitute of Bi and Li. It is interesting to note that the loss tangent of the co-substituted compositions are lower than that of the parent composition and it decreases approximately with increasing extent of co-substitution. This property is quite useful to develop this material further for capacitor applications. The transition temperature has shifted from 120 °C of pure BaTiO₃ towards higher temperatures to 150, 160 and 175 °C with (Bi, Li)_x where x = (0.02, 0.04 and 0.08), respectively of co-substitution BaTiO₃. The change is linear with the degree of co-substitution.     

Low-temperature synthesis of the multiferroic compound BiFeO<Subscript>3</Subscript>

A novel, low-temperature process is proposed for the synthesis of the multiferroic compound BiFeO₃. It enables the preparation of nanoparticulate material at temperatures as low as 200–250°C. An important role in the low-temperature synthesis of bismuth orthoferrite is played by ammonium nitrate additions and excess bismuth oxide.     

Multifunctional performance of gC<Subscript>3</Subscript>N<Subscript>4</Subscript>-BiFeO<Subscript>3</Subscript>-Cu<Subscript>2</Subscript>O hybrid nanocomposites for magnetic separable photocatalytic and antibacterial activity

Highly active gC₃N₄-BiFeO₃-Cu₂O nanocomposites were successfully prepared via a facile, cost effective and eco-friendly method of hydrothermally wet precipitation combined with ultrasonic dispersion process. The prepared samples were characterized by XRD, FTIR, HRSEM, EDS, TEM, UV–Vis DRS, PL, VSM, BET and electrochemical properties. By means of these analysis for examine the crystal phase, nanostructure, band gap and light-harvesting properties were carried out. UV-DRS spectra indicate that the bandgap of g-C₃N₄ (2.7 eV) reduced to 2.59 and 2.21 eV by mixed with corresponds to BiFeO₃ and BiFeO₃/Cu₂O nanomaterials. The ideal photocatalytic activity of the gC₃N₄-BiFeO₃-Cu₂O nanocomposites, where RhB dye under visible light irradiation which was up to 4.36 and 2.52 times as the higher photodegradation ability to compare pristine g-C₃N₄ and gC₃N₄-BiFeO₃ catalyst. The magnetization was confirmed by VSM studies, and hence, after the photocatalytic reaction, the magnetically separable catalyst can be quickly separated from the water by an external magnetic field. The superior photocatalytic performance is due to the synergistic effect on the interface of BiFeO₃/Cu₂O in the gC₃N₄-BiFeO₃-Cu₂O nanocomposites has reduced the bandgap which enables high separation efficiency of the charge carrier, suppressed recombination rate and their high surface area. Moreover, the chief gC₃N₄-BiFeO₃-Cu₂O catalyst can exhibited the lesser charge transfer resistance (impedance), enhances of photocurrent responses, whereas exposed to the development of photocatalytic appearance and more charge carrier ability. Also, the antibacterial activity of the gC₃N₄-BiFeO₃-Cu₂O nanocomposite has showing a well deactivation in both G⁺ (S. aureus) and G^? (E. coli) bacteria’s whereas compare to other prepared samples.     

Structure and electrical properties of MnO doped (Ba<Subscript>0.96</Subscript>Ca<Subscript>0.04</Subscript>)(Ti<Subscript>0.92</Subscript>Sn<Subscript>0.08</Subscript>)O<Subscript>3</Subscript> lead free ceramics

In this work, (Ba_0.96Ca_0.04)(Ti_0.92Sn_0.08)O₃–xmol MnO (BCTS–xMn) lead-free piezoelectric ceramics were fabricated by the conventional solid-state technique. The composition dependence (0 ≤ x ≤ 3.0 %) of the microstructure, phase structure, and electrical properties was systematically investigated. An O–T phase structure was obtained in all ceramics, and the sintering behavior of the BCTS ceramics was gradually improved by doping MnO content. In addition, the relationship between poling temperature and piezoelectric activity was discussed. The ceramics with x = 1.5 % sintering at temperature of 1330 °C demonstrated an optimum electrical behavior: d ₃₃ ~ 475 pC/N, k _p ~ 50 %, ε _r ~ 4060, tanδ ~ 0.4 %, P _r ~ 10.3 μC/cm², E _c ~ 1.35 kV/mm, T _C ~ 82 °C, strain ~0.114 % and \(d_{33}^{*}\) ~ 525 pm/V. As a result, we achieved a preferable electric performance in BaTiO₃-based ceramics with lower sintering temperature, suggesting that the BCTS–xMn material system is a promising candidate for lead-free piezoelectric ceramics.     

Effect of BaTiO<Subscript>3</Subscript> heat treatment on the microstructure and dielectric properties of BaTiO<Subscript>3</Subscript>-based ceramics

We have studied the effect of heat treatment of the starting BaTiO₃ powder on the dielectric properties and microstructure of X7R-type BaTiO₃-based ceramics. The results demonstrate that annealing of BaTiO₃ stabilizes the degree of tetragonality in the crystal lattice of the ceramics. Microstructural analysis shows that the annealing temperature has no effect on the average grain size of the ceramics. Increasing the BaTiO₃ annealing temperature increases the dielectric permittivity of the core phase and reduces the temperature coefficient of capacitance (TCC). We obtained an X7R-type BaTiO₃-based ceramic material (BaTiO₃ annealing temperature, 1150°C; firing temperature, 1160°C) with the following properties: ɛ_25°C = 2230, TCC = ±12% (−55 to 125°C), and tanδ_25°C = 0.013.     

Structural,dielectric and impedance spectroscopy studies of (Na<Subscript>0.5</Subscript>Bi<Subscript>0.5</Subscript>)(Zr<Subscript>0.025</Subscript>Ti<Subscript>0.975</Subscript>)O<Subscript>3</Subscript> ceramic

Structural, vibrational, dielectric and electrical properties of (Na_0.5Bi_0.5)(Zr_0.025Ti_0.975)O₃ ceramic synthesized by the solid-state reaction technique have been carried out. The X-ray diffraction analysis was indicated as a pure perovskite phase in the rhombohedral structure. The modes of rhombohedral vibrations were appeared in the experimental Raman spectrum at room temperature. The dielectric and electrical properties of the material were investigated by impedance spectroscopy analysis for a broad range of temperatures (50–560 °C) and frequency domain of 10²?10⁶ Hz. The dielectric measurement exhibit two phase transitions: a ferro-antiferroelectric transition followed by an antiferro-paraelectric transition at higher temperatures. Complex impedance analysis was carried out in order to distinct the contribution of the grains and the grain boundaries to the total electrical conduction. The Nyquist plot was proved to be a non-Debye relaxation mechanism. The combined spectroscopic plots of the imaginary part of electric impedance and modulus confirmed the non-Debye type behavior. The frequency dependent ac conductivity obeys the double power law behavior and shows three types of conduction process. The significant decrease of dc conductivity spectrum followed the Arrhenius relationship. The values of calculated activation energy of the compound implied that the electrical conduction is mostly due the high oxygen mobility.     

Study on carbon quantum dots/BiFeO<Subscript>3</Subscript> heterostructures and their enhanced photocatalytic activities under visible light irradiation

Carbon quantum dots/Bismuth ferrite (CQDs/BiFeO₃) composite materials were successfully synthesized by a facile hydrothermal treatment of Fe(NO₃)₃·9H₂O, Bi(NO₃)₃·5H₂O and CQDs solutions. The structural and optical characteristics of the composite materials were characterized by X-ray diffraction, Fourier transform infra-red spectroscopy, transmission electron microscopy and ultraviolet–visible absorption, respectively. The photocatalytic activities of pure BiFeO₃, CQDs and CQDs/BiFeO₃ composite materials had also been carried out by using Rhodamine B as test stuff. The experimental results indicated that for QDs/BiFeO₃ composite materials, the CQDs were attached to the surfaces of BiFeO₃ materials, CQDs and BiFeO₃ belong to different phase. Owing to the heterojunction formed at the interface between CQDs and BiFeO₃ materials together with CQDs as an electron reservoir, the photocatalytic activities of CQDs/BiFeO₃ composite materials were significantly improved. Especially, the CQDs/BiFeO₃ composite sample with 3.3 wt% CQDs has the highest degradation rate, which was about 7.3, 3.7 times higher than those of pure BiFeO₃ and CQDs, respectively. Moreover, the mechanism of RhB degradation catalyzed by CQDs/BiFeO₃ composite materials was also thoroughly explained.     

Modulus spectroscopy of lead potassium titanium niobate (Pb<Subscript>0.95</Subscript>K<Subscript>0.1</Subscript>Ti<Subscript>0.25</Subscript>Nb<Subscript>1.8</Subscript>O<Subscript>6</Subscript>) ceramics

The modulus Spectroscopy of Lead Potassium Titanium Niobate (Pb_0.95K_0.1Ti_0.25Nb_1.8O₆, PKTN) Ceramics was investigated in the frequency range from 45 Hz to 5 MHz and the temperature, from 30 to 600 °C. XRD analysis in PKTN indicated a orthorhombic structure with lattice parameters a = 18.0809 Å, b = 18.1909 Å and c = 3.6002 Å. The dielectric anomaly with a peak was observed at 510 °C. Variation of ε^I and ε^II with frequency at different temperatures exhibit high values, which reflects the effect of space charge polarization and/or conduction ion motion. The electrical relaxation in ionically conducting PKTN ceramic analyzed in terms of Impedance and Modulus formalism. The Cole–Cole plots of impedance were drawn at different temperatures. The dielectric modulus, which describes the dielectric relaxation behaviour is fitted to the Kohlrausch exponential function. Near the phase transition temperature, a stretched exponential parameter β indicating the degree of distribution of the relaxation time has a small value. From the AC conductivity measurements the activation energy near phase transition temperature (T _C°C) has been found to different from that of the above and below T _C. The temperature dependence of electrical modulus has been studied and results are discussed.     

Light weight RGO/Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanocomposite for efficient electromagnetic absorption coating in X-band

Reduced graphene oxide (RGO)/magnetite (Fe₃O₄) nanocomposite has been synthesized by an in-situ facile hydrothermal method. The XRD pattern reveals the development of nanocomposite in which both phases are coexistent. Raman Spectroscopy shows the main characteristics peaks of D and G bands at 1349 cm^?1 and 1595 cm^?1 for graphitic structures. The intensity ratio (I_D/I_G) is also calculated, which indicate the degree of defects in the material. This ratio (I_D/I_G), increases from 0.84 for GO to 0.91 for RGO/Fe₃O₄ nanocomposite and promotes the defects which are beneficial for electromagnetic (EM) absorption. The SEM image depicts that, Fe₃O₄ spherical nanoparticles are dispersed over the surface of graphene sheets and provide a thermal conducting path for heat dissipation between different layers of graphene. The EM absorption properties have been analyzed at 2–18 GHz of RGO and RGO/Fe₃O₄. The addition of proper content of Fe₃O₄ magnetic nanoparticles in RGO sheets improved the Reflection Loss (RL) from ??13.5 dB to ??20 dB at a frequency of 9.5 GHz. Moreover, due to magnetic loss and interfacial polarization, the effective bandwidth increases from 2.5 GHz to 3.8 GHz at a coating thickness of 1.5 mm. Hence this light weight nanocomposite is an excellent material for strong EM absorption in X-band.     

Structural and electrical properties of Bi5Ti3FeO15 ceramics

Bi₅Ti₃FeO₁₅ (BTF) is a multiferroic material of Aurivillius structural family with (perovskite) layered structure. This material has special interest and position in the family because it is a combination of multiferroic BiFeO₃ and ferroelectric Bi₄Ti₃O₁₂, and can be used as new magneto-electric material for devices. The compound (Bi₅Ti₃FeO₁₅) was synthesized by a standard and widely used a high-temperature solid-state reaction method using high purity oxides. Preliminary structural analysis of the compound from the room temperature X-rays diffraction data confirmed the formation and good quality of the material. The nature of the microstructure (i.e., distribution, size and shape of grains, etc.) of sample recorded at room temperature using scanning electron microscopy exhibits formation of high-density sample. Studies of capacitive (permittivity and tangent loss) and resistive (impedance, electrical modulus and electrical conductivity) properties of the material as a function of frequency (1–1,000 kHz) at different temperatures (30–500 °C) using a complex impedance spectroscopy technique have provided many interesting and vital information on contribution of grains, grain boundary and interface in the material.     

Magnetoelectric interactions in BiFeO<Subscript>3</Subscript>, Bi<Subscript>0.95</Subscript>Nd<Subscript>0.05</Subscript>FeO<Subscript>3</Subscript>, and Bi<Subscript>0.95</Subscript>La<Subscript>0.05</Subscript>FeO<Subscript>3</Subscript> multiferroics

The technology of ceramic BiFeO₃, Bi_0.95Nd_0.05FeO₃, and Bi_0.95La_0.05FeO₃ multiferroics is described. The room-temperature magnetization, magnetoelectric (ME), and magnetodielectric (MDE) effects in these compounds have been studied. It is established that even a small fraction (x = 0.05) of rare-earth additives (La, Nd) to bismuth ferrite not only enhance its magnetic properties, but also significantly influence the ME and MDE effects. The dependence of the ME effect on the frequency of modulation of the alternating magnetic field in Bi_0.95Nd_0.05FeO₃, and Bi_0.95La_0.05FeO₃ is more pronounced than in pure BiFeO₃.     

Investigation of Li<Subscript>2</Subscript>Zn<Subscript>3</Subscript>Ti<Subscript>4</Subscript>O<Subscript>12</Subscript>-based temperature stable dielectric ceramics for LTCC applications

A low temperature co-fired ceramic (LTCC) was fabricated at 910 °C /2 h from the powder mixture of Li₂Zn₃Ti₄O₁₂, TiO₂ and a B₂O₃–La₂O₃–MgO–TiO₂ glass (BLMT), and the influence of TiO₂ on microstructure and dielectric properties of the composite was investigated in the composition range (wt%) of 20BLMT–(80???x)Li₂Zn₃Ti₄O₁₂–xTiO₂ (x?=?0, 2.5, 5, 7.5, 9 and 10). The results showed that all samples consisted of Li₂Zn₃Ti₄O₁₂, TiO₂, LaBO₃ and LaMgB₅O₁₀ phase. And LaBO₃, LaMgB₅O₁₀ and a small amounts of TiO₂ were crystallized from BLMT glass during sintering process. As x increases, dielectric constant and temperature coefficient of resonance frequency of the composites demonstrated gradually increase, whereas the quality factor of the sample of x?=?0 wt% was about 41,500 GHz and the ones maintained stable at a high level of 49,000–51,000 GHz for other samples. The composite with x?=?9 wt% had an optimal microwave dielectric properties with the dielectric constant of 20.2, quality factor of 50,000 GHz and temperature coefficient of resonant frequency of ??0.33 ppm/°C.     

Dielectric relaxation phenomena in the compound: LiCo<Subscript>3/5</Subscript>Mn<Subscript>1/5</Subscript>Cu<Subscript>1/5</Subscript>VO<Subscript>4</Subscript>

Solution-based chemical method has been used to produce LiCo_3/5Mn_1/5Cu_1/5VO₄ ceramics. The formation of the compound is checked by X-ray diffraction analysis and it reveals an orthorhombic unit cell structure with lattice parameters of a = 9.8262 Å, b = 3.0706 Å, c = 14.0789 Å. Field emission scanning electron micrograph indicates a polycrystalline texture of the material with grains of unequal sizes (~0.2 to 3 μm). Complex impedance spectroscopy technique is used to study the dielectric properties. Temperature dependence of dielectric constant (ε _r) at various frequencies exhibits the dielectric anomalies in ε _r at T _c (transition temperature) = 245, 255, 260 and 265 °C with (ε_r)_max. ~458, 311, 214 and 139 for 50, 100, 200 and 500 kHz, respectively. Frequency dependence of tangent loss at various temperatures shows the presence of dielectric relaxation in the material.     

Structural,electrical and magnetic properties of Mn<Subscript>3</Subscript>O<Subscript>4</Subscript>/MgO nanocomposite

The present paper deals with the synthesis of Mn₃O₄/MgO nanocomposite through a simple sol–gel route and their electrical and magnetic properties are discussed for electrode applications. The grain size and particle morphology of the synthesized nanocomposite are characterized using XRD and HRSEM. The elemental compositions of the synthesized samples were analyzed using EDAX spectra. The dielectric constant, dielectric loss and AC conductivity of the synthesized samples were studied in the frequency range of 100 Hz–5 MHz at different temperatures (303–573 K) using impedance spectra. The activation energy was calculated using Arrhenius plot. The vibrating sample magnetometry (VSM) study shows that the nanocomposites are found to be paramagnetic at room temperature.