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Ferroelectric–magnetic composites of SrBi2Nb2O9–CoFe2O4 (SBN–CFO) were synthesized via conventional solid state reaction route. The powder X-ray diffraction, Raman spectroscopy and scanning electron microscopy measurements confirm the existence of two chemically separated phases and phase purity in the SBN–CFO composites. Magnetization measurements confirm the enhanced values of the magnetic parameters. The change in the area of the ferroelectric P vs. E loops with frequency confirms the enhanced ferroelectric nature of the SBN–CFO composites. The quantified maximum values of magnetoelectric coefficient (α) are observed from the P vs. E loop measurements in the influence of applied magnetic field and found to be 4.475 mV cm−1 Oe−1 at 688 Oe for SBN–0.1CFO and 3.389 mV cm−1 Oe−1 at 1000 Oe for SBN–0.2CFO composites, respectively. The shifting in the peaks of temperature-dependent dielectric maxima towards the higher temperature side confirms the relaxor behaviour in the SBN–CFO composite samples. [ABSTRACT FROM AUTHOR]

The present work is focused on the structural, microstructural, dielectric, multiferroic properties, including magnetoelectric coupling and energy storage density analysis of Mn modified multiferroic BiFeO3 (BFO) samples. The samples were prepared via solid state reaction method. The structural and microstructural properties were investigated using powder x-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The single phase of Mn modified multiferroic BFO was confirmed from XRD patterns which exhibited predominantly a majority phase of BFO. SEM micrographs indicated decrease in grain size and more homogeneous grain structure with the increase of Mn content into the BFO. A nonzero value of coercivity was obtained in the 5% Mn BFO (BFMO5) sample, which confirmed the antiferromagnetic to weak ferromagnetic change. Composition dependent P versus E ferroelectric hysteresis loop measurements confirmed the enhanced ferroelectric nature of the samples. An enhanced value of energy storage density (13.71 mJ/cm3 and 34.86 mJ/cm3) was achieved for BFMO3 and BFMO5 samples. The frequency dependent and magnetic field dependent measurements of P versus E hysteresis and dielectric anomaly near the magnetic transition temperature confirmed qualitative, as well as quantitative, magnetoelectric (ME) coupling, including the maximum value of ME coupling coefficient (α ≈ 3.36584 mVcm−1 Oe−1 at a field of 2696 Oe) obtained for the BFMO5 sample. Enhanced values of dielectric and impedance parameters were observed in the Mn modified BFO samples. [ABSTRACT FROM AUTHOR]

The paper reports the influence of lanthanum substitution on the structural, dielectric and piezoelectric properties of PZT. Polycrystalline samples were synthesized by solid state reaction technique. XRD analysis shows all the samples to be single phase with perovskite structure, initially showing rhombohedral structure and then transforming into rhombohedral. The transition temperature (Tc) was observed to decrease monotonically with increasing x. The results showed that, after poling, the dielectric constant decreased for rhombohedral composition but increased for tetragonal compositions. Electromechanical coupling factor (kp) was found to increase with x and becomes saturate at x = 0.07 mol%. Composition with x = 0.07 gives maximum value of kp = 52% and d33 = 450 pC/N. All the samples depict well defined ferroelectric behavior. [ABSTRACT FROM AUTHOR]

Here we are reporting influence of Nd substitution on properties of Zr modified BaTiO3 [(BaZrxTi1-xO3), BZT5)]. The composition Ba1-xNdx(Zr0.05Ti0.95)O3 (x = 0-0.04) was prepared by conventional solid state reaction route. The sintered sample was characterized for its structural properties by XRD and Raman analysis. The dielectric properties were measured as a function of temperature in the frequency range of 100 Hz to 500 KHz. A high value of dielectric constant (∼23,000) is observed at room temperature as compared to undoped BaTiO3 (∼2500). It also observed that the three phase transition temperatures corresponding to pure BZT5 merge with substitution and exhibit a single ferroelectric to paraelectric phase transition. The value of remnant polarization and coercive field at room temperature were obtained from polarization vs electric field loop measurement on unpoled ceramic sample. [ABSTRACT FROM AUTHOR]

We report the comparison of structural, dielectric, ferroelectric and piezoelectric properties of lanthanum-modified lead zirconate titanate (PLZT) ceramics with the substitution of 7 and 8 mol% La3+ content in PZT (65/35) by three different formulations. The three formulations are (i) cation compensated at A-site, (ii) valency compensated at A-site and (iii) all sites (A and B) compensated. Samples were prepared by solid-state reaction route. X-ray diffraction (XRD) study shows single-phase formation with rhombohedral structure in all the samples. Scanning electron microscopy (SEM) study shows variation in grain size with different formulations. Dielectric studies for all the PLZT samples have been carried out as a function of temperature (room temperature to 350°C) at few selected frequencies (0.1, 1, 10 and 100 kHz) showing characteristics of diffuse phase transition (DPT). Dielectric properties of the poled and unpoled samples at room temperature have also been compared. All these compositions show well-defined ferroelectric behavior with significant change in the coercive field (Ec). Maximum piezoelectric properties have been obtained for the PLZT system with 8 mol% La3+ prepared by formulation (i). [ABSTRACT FROM AUTHOR]

The effect of niobium doping on the structure and electrical properties with the following compositions Pb(Zr0.52Ti0.48)1-5X/4NbXO3 with 0

The structural and dielectric properties of a PZN-PLZT solid solution were investigated. The formation of a single phase was studied by the addition of PLZT (8/60/40) in the present system. With the increase of PLZT, the content of the pyrochlore phase decreased significantly and PZN ceramics with 100% perovskite phase could be achieved with x>0.6. Dielectric properties were investigated as a function of temperature and frequency. The ferroelectric hysteresis loop shows typical characteristics of ferroelectrics. [ABSTRACT FROM AUTHOR]

Lead magnesium niobate titanate, PMNT 68/32, ceramic was prepared by a sol–gel technique using alkoxide precursors. Perovskite phases with mixed structure (rhombohedral and tetragonal) were identified by X-ray diffraction (XRD). A dense and homogeneous distribution of sub-micron-size grains was obtained from a scanning electron microscopy (SEM) study. The dielectric response showed relaxor behavior of the material with a transition temperature of ~130°C at 1?kHz. The polarization versus electric field ( P – E ) hysteresis loop with a remnant polarization, P r, of ~28?µC/cm 2 and a coercive field, E c, of ~4.2?kV/cm confirmed the ferroelectric nature of the material. The room temperature values of the piezoelectric coefficient, d 33, and the pyroelectric coefficient, p i, were found to be ~300?pC/N and ~56?nC/cm 2 ?K, respectively. The development of high strain with a large hysteresis in the strain versus electric behavior was related to the morphotropic phase boundary (MPB) nature of the material. [ABSTRACT FROM AUTHOR]