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In the present communication, studies of some physical properties (i.e., crystal data, permittivity, impedance, electrical cobnduction and magnetic) of a multiferroic material with a chemical composition (SmLi)1/2(Fe2/3Mo1/3)O3 have been reported. Thermogravimetric analysis of the compound, prepared by cost effective ceramic technology processing, was executed to check the mass loss as well as the required decomposition temperature of the ingredients. An analysis of X-ray spectra or pattern suggests that the crystallization phase or cystal system of the compound at room temperature is orthorhombic. The broad studies of dielectric properties {relative dielectric constant (εr), and tangent loss (tan δ)} display their independence of temperature and frequency in the rage of (30-375 °C) and (1 kHz-1 MHz) respectively. The impedance spectroscopic technique has provided a considerable significant information regarding the grain, grain boundary contribution within the sample and relaxation mechanism of the compound. The occurrence of negative temperature coefficient behaviour (NTCR) is depicted by the further analysis of impedance parameters. The frequency-temperature dependence of conductivity follows the Johnson’s power Universal law. The Arrhenius plot (i.e., variation of electrical conductivity with temperature) is used to calculate the activation energy. Analysis of magnetization (M-H) loop shows weak ferromagnetism of the compound. The material possesses significantly high magnitude of magnetoelectric coefficient of 3.0 mV Cm− 1 Oe− 1. [ABSTRACT FROM AUTHOR]

Double perovskites have been extensively studied in materials chemistry due to their excellent properties and novel features attributed to the coexistence of ferro/ferri/antiferro-magnetic ground state and semiconductor band gap within the same material. Double perovskites with Sr2NiMO6 (M = Te, W) structure type have been synthesized using simple, non-toxic and costless aqueous citrate sol-gel route. The reaction yielded phase-pure nanocrystalline powders of two compounds: Sr2NiWO6 (SNWO) and Sr2NiTeO6 (SNTO). According to the Rietveld refinement of powder X-ray diffraction data at room temperature, Sr2NiWO6 is tetragonal (I4/m) and Sr2NiTeO6 is monoclinic (C12/m1), with average crystallite sizes of 49 and 77 nm, respectively. Structural studies have been additionally performed by Raman spectroscopy revealing optical phonons typical for vibrations of Te6+/W6+O6 octahedra. Both SNTO and SNWO possess high values of dielectric constants (341 and 308, respectively) with low dielectric loss (0.06 for SNWO) at a frequency of 1 kHz. These values decrease exponentially with the increase of frequency to 1000 kHz, with the dielectric constant being around 260 for both compounds and dielectric loss being 0.01 for SNWO and 0.04 for SNTO. The Nyquist plot for both samples confirms the non-Debye type of relaxation behavior and the dominance of shorter-range movement of charge carriers. Magnetic studies of both compounds revealed antiferromagnetic behavior, with Néel temperature (TN) being 57 K for SNWO and 35 K for SNTO. [ABSTRACT FROM AUTHOR]

Some yttrium modified BiFeO 3 –PbTiO 3 (BYFO-PT) compounds have been fabricated using a standard ceramic technology (solid-state route). The structural analysis from X-ray diffraction (XRD) data ensures the formation of the rhombohedral phase of the compounds. The prepared materials have major bismuth ferrite (70%) and lead titanate (30%) with few impurity phases. The materials are found to have a high dielectric constant and low tangent loss. The relaxation mechanism is identified from the peaks appearing in impedance and modulus curves. The materials show a negative temperature coefficient of resistance (NTCR) semiconductor type behavior in the temperature range of 250 °C–400 °C. In addition, grain and grain boundary effects are observed through the Nyquist plots. The activation energy (E a) of the compounds is calculated from the slope of inverse temperature versus AC conductivity at the high-temperature range. The ferroelectric nature of the compounds is confirmed by electric field dependent polarization (PE-hysteresis) loops. Image 10942 • The preferred 0.7BYFO-0.3 PT ceramics are coming under compositional morphotropic phase boundary (MPB) region. • Dielectric, electrical, ferroelectric properties are revealed. • High dielectric permittivity and less dielectric loss are achieved after Y substitution. • Nyquist plots relate the grain and grain boundary contributions. • A well defined relaxation mechanism was identified by modulus analysis. [ABSTRACT FROM AUTHOR]

Dense and stoichiometric Ba 0.8 Mg 0.2 (Zr 0.1 Ti 0.8 Ce 0.1) O 3 (BMZTCO) ceramics have been synthesised and their excitation was experimentally evaluated by applying an electric field. The processed sample exhibits superior frequency-independent and temperature-dependent dielectric parameters. The prepared sample has combined the tetragonal and cubic phases of BaTiO 3 and Ce 2 O 3 . The Bode plots suggest non-Debye type of relaxation mechanism and positive temperature coefficient-type behaviour. The excitation intensity reaches a peak when the driving frequency matches with the natural frequency of the prepared sample. [ABSTRACT FROM AUTHOR]

In the present work, the fused silica was fabricated using colloidal processing route. The fabricated samples were quenched (five time thermal cycling) and the results of the structural and electrical properties of the sintered sample and quenched sample have been studied and compared. The structural analysis confirmed the formation of the fabricated ceramics. The morphology of the sample suggested that there is close packing of the grains. The relaxation and conduction mechanism were analyzed using impedance and modulus spectroscopy. The dielectric parameters were inspected on varying temperature and frequency range. The impedance study showed the dependence of electrical properties on both frequencies and temperatures having corresponded with the morphology. [ABSTRACT FROM AUTHOR]

The bulk ceramics bearing chemical formula BiFeO3 and (BiLi)1/2(Fe2/3Mo1/3)O3 (abbreviated as BFO and BLFMO respectively) are synthesized using mixed oxide route. The physical properties (structural, dielectric, electric and magnetic) are tailored in Li and Mo co-doped BiFeO3. The phase evolution suggests that there is transformation from rhombohedral (pure BFO) to orthorhombic (BLFMO). Micro-structural suggests that due to co-doping the size of the grain is smaller than BFO. The dielectric properties of both BFO and BLFMO measure with an LCR meter varying the frequency (102–106 Hz) and temperature (30–375 °C). The leakage current decreases in BLFMO. The magnetic hysteresis loop owing weak ferromagnetism is depicted for Li and Mo co-doped BFO. The fabricated material will be base for various applications like filter and buffering. [ABSTRACT FROM AUTHOR]

The barium doped bismuth sodium titanate (i.e., Bi0.49Na0.490.98Ba0.02)TiO3 (BNBT) powder was prepared by a conventional ceramic processing route. The thin film composites of BNBT- PVDF (polyvinylidene fluoride) were fabricated via a solution casting route. The scanning electron micrographs of the thin film samples show the homogenous distribution of grains with absence of cracks/pores. It is observed that with the increase of BNBT content in PVDF leads to enhancement in the dielectric permittivity and the reduction in the dissipation factor (tangent loss). The various electrical properties of the thin film samples were studied in the frequency range of 1 kHz to 1 MHz at different temperature between 25 and 100 °C. The prepared composite films have been used to study the (a) relationship between properties and crystal structure and (b) relaxation and conduction mechanism through the complex modulus and impedance spectroscopy. The contribution of grains was analyzed in the composite films by the fitting of equivalent circuit with the experimental data. An existence of the non-Debye type of dielectric relaxation was indicated by studying of the impedance and modulus parameters. The calculated activation energy from the temperature dependence of AC conductivity depicts hopping nature of charge carriers, which further explain the conduction process and mechanism in the prepared composites. [ABSTRACT FROM AUTHOR]

The bulk ceramics bearing chemical formula BiFeO3 and (BiLi)1/2(Fe2/3Mo1/3)O3 (abbreviated as BFO and BLFMO respectively) are synthesized using mixed oxide route. The physical properties (structural, dielectric, electric and magnetic) are tailored in Li and Mo co-doped BiFeO3. The phase evolution suggests that there is transformation from rhombohedral (pure BFO) to orthorhombic (BLFMO). Micro-structural suggests that due to co-doping the size of the grain is smaller than BFO. The dielectric properties of both BFO and BLFMO measure with an LCR meter varying the frequency (102–106 Hz) and temperature (30–375 °C). The leakage current decreases in BLFMO. The magnetic hysteresis loop owing weak ferromagnetism is depicted for Li and Mo co-doped BFO. The fabricated material will be base for various applications like filter and buffering. [ABSTRACT FROM AUTHOR]