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The effect of Sm doping on structural, dielectric, multiferroic and electrical properties of GaFeO3 with composition GaFe1-xSmxO3 (x = 0, 0.05, 0.10, 0.15) is studied. Rietveld refinement of the XRD data reveals the formation of single-phase orthorhombic structure. It is observed that the unit cell volume increases with rise in Sm content. FESEM study reveals that the irregular-shaped grains are uniformly distributed throughout the surface. From dielectric plot, a significant variation in εr and tanδ with Sm content is observed. Further, conjugate existence of both ferroelectric and magnetic ordering is confirmed by polarisation and magnetization hysteresis loop measurement. The remanent polarisation (Pr) is decreased with Sm content due to the defects related to fluctuations in the valance of Fe in the studied samples. Also, the remanent magnetization (Mr) is found to fall with rise in Sm content due to the lower magnetic moment (μ) of Sm3+. Impedance analysis shows the existence of two types of relaxation in studied materials. [ABSTRACT FROM AUTHOR]

Ba0.70Sr0.30TiO3-(BST) ceramics were fabricated by conventional mixed oxide route. The structural phase transition, ferroelectric, dielectric and energy storage properties of BST ceramics capacitors were investigated. Electric field induced weak ferroelectricity is observed for BST ceramics. Temperature dependent dielectric property measurements of BST solid-solutions have shown a high dielectric constant and low dielectric loss. Room temperature breakdown field strength and energy densities were obtained from P-E loops. The recoverable energy density is 0.17 J/cm3with dielectric breakdown strength as high as 150 kV/cm. BST ceramics have shown interesting energy densities; these might be the strong candidate materials for capacitor applications. [ABSTRACT FROM AUTHOR]

This article presents the effect of lead-borosilicate glass (65PbO 20B 2 O 3 15SiO 2 , mol%) (PBS) addition on the structure, microstructure, dielectric, ferroelectric and energy storage properties of Ba 0.9995 La 0.0005 TiO 3 (BLT) ceramics system has been systematically investigated. XRD analysis revealed the tetragonal (T) phase at room temperature. Addition of PBS glass results in decrease in ferroelectricity and improved breakdown properties. High maximum polarization (P s ∼21.53 μC/cm 2 ) and remnant polarization values (2P r ∼8.75 μC/cm 2 ) were obtained from ferroelectric (P-E) hysteresis loops for the BLT ceramics. Two dielectric anomalies at 420 K and 600 K were observed due to the phase transformation. The glass-ceramics heat treated at 900 °C for 3 h was found to possess optimal properties with breakdown strength of >300 kV/cm and energy storage density of 0.564 J/cm 3 , which is a promising glass-ceramic ferroelectric capacitor material for high energy storage density dielectrics. [ABSTRACT FROM AUTHOR]

Ba0.70Ca0.30TiO3-(BCT),Ba(Zr0.2Ti0.8)O3-(BZT) ceramics were fabricated by conventional mixed oxide route to develop inorganic dielectric materials suitable for use as an insulator with high dielectric constant and low energy loss for capacitor applications. The structural phase transition, ferroelectric, dielectric and energy storage properties of BCT, BZT ceramic capacitors were investigated. Room temperature X-ray diffraction (XRD) patterns revealed prominent peaks corresponding to tetragonal perovskite crystal structure for both BCT, BZT solid solutions. Slim ferroelectric hysteresis (P-E) loops were observed for BCT, BZT solid solutions. Temperature dependent dielectric property measurements of BCT, BZT solid solutions have shown a high dielectric constant and low dielectric loss. Room temperature (300K) breakdown field strength and energy densities were obtained from the integral area of P-E loops. For the BCT ceramics, the largest recoverable energy (unreleased energy) density is 1.41 J/cm3with dielectric breakdown strength as high as 150 kV/cm. For the BZT ceramics, the largest recoverable energy (unreleased energy) density is 0.71 J/cm3with dielectric breakdown strength as high as 150 kV/cm. Bulk BCT, BZT ceramics have shown interesting energy densities; these might be the strong candidate materials for capacitor applications. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the development of a lead free {Ba(Zr0.2Ti0.8)O3}(1−x){(Ba0.7Ca0.3)TiO3} x – x=0.10, 0.15 and 0.20 – BZT–BCT ceramic solid solution system prepared using a solid-state reaction technique. The evolution of the Raman spectra with temperature was used to study the variation of the basic phase transition of BaTiO3 in these compositions. The phase transition temperature on heating was found to decrease to 310K, 300K, and 300K, respectively, with increasing Ca content on BCT end and decreasing Zr content on BZT end of lead free pseudobinary ferroelectric BZT–BCT system. Tetragonal and rhombohedral phase coexistence is observed at room temperature from X-ray diffraction (XRD) spectra. Rhombohedral phase is identified between the 83K and 273K from temperature dependent Raman studies. Raman results are in excellent agreement with those obtained from temperature dependent dielectric measurements. Bulk ceramic BZT–BCT materials have shown interesting temperature dependent dielectric properties and as well as higher values of room temperature dielectric constant ∼7800, 8400, 5200, dielectric tunability ∼82%, figure of merit (FOM) ∼93.71 % with low dielectric loss (tan δ) ∼0.015 to 0.024 and good thermal stability at high sintering temperature (1600°C); they might be one of the strong candidates for dielectric tunable capacitor applications in an environmentally protective atmosphere. [Copyright &y& Elsevier]

The effect of Sm doping on structural, dielectric, multiferroic and electrical properties of GaFeO3 with composition GaFe1-xSmxO3 (x = 0, 0.05, 0.10, 0.15) is studied. Rietveld refinement of the XRD data reveals the formation of single-phase orthorhombic structure. It is observed that the unit cell volume increases with rise in Sm content. FESEM study reveals that the irregular-shaped grains are uniformly distributed throughout the surface. From dielectric plot, a significant variation in εr and tanδ with Sm content is observed. Further, conjugate existence of both ferroelectric and magnetic ordering is confirmed by polarisation and magnetization hysteresis loop measurement. The remanent polarisation (Pr) is decreased with Sm content due to the defects related to fluctuations in the valance of Fe in the studied samples. Also, the remanent magnetization (Mr) is found to fall with rise in Sm content due to the lower magnetic moment (μ) of Sm3+. Impedance analysis shows the existence of two types of relaxation in studied materials. [ABSTRACT FROM AUTHOR]