Structural and impedance spectroscopy analysis of Ba(Fe_1/2Nb_1/2)O₃ ceramic

Abstract

Lead-free perovskite Ba(Fe 1/2 Nb 1/2 )O 3 (BFN) was prepared by conventional ceramic fabrication technique at 1200 8C/5 h in air atmosphere. The crystal symmetry, space group, and unit cell dimensions were determined from the experimental results using FullProf software whereas crystallite size and lattice strain were estimated from Williamson-Hall approach. X-ray diffraction (XRD) analysis of the compound indicated the formation of a single-phase monoclinic structure with the space group P2/m. EDAX and SEM studies were carried out in order to evaluate the quality and purity of the compound. To find a correlation between the response of the real system and idealized model circuit composed of discrete electrical components, the model fittings were presented using the impedance data. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. The correlated barrier hopping (CBH) model was employed to successfully explain the mechanism of charge transport in BFN.

Dielectric relaxation in Ba(Y1/2Nb1/2)O3–BaTiO3 ceramics

“…The values of the index s were obtained from the slopes of the plots in the low frequency region, which always comes out to be less than 1 and are decreasing with the rise in temperature. This observation is consistent with correlated barrier hopping model [36]. Therefore, the electrical conduction in the system may be considered due to the short range translational type hopping of charge carriers.…”

Complex impedance properties of LiSr2Nb5O15 ceramic

“…7. An anomaly observed near 100 kHz may be due to the onset of the conductivity relaxation, which indicates the translation from long range hopping to the short range ion motion [30] similar to M" with frequency. Figure 7 shows the variation of dc (bulk) conductivity with inverse of temperature (10 3 /T).…”

“…Ceramics with filled tungsten bronze (TB) structure [1] have received much scientific and technological attention due to their interesting dielectric, ferroelectric, pyroelectric, piezoelectric and nonlinear optic properties which have been used for various electronic devices applications such as capacitors, actuators, pyroelectric detectors, transducers, electro-optic, ferroelectrics random access memory [2][3][4][5][6] 30 , where A-sites are occupied by mono or trivalent cations, B-sites are occupied by penta or hexavalent ions and C-sites are being small, often remains vacant or may be filled by mono or divalent cations. The distribution of metal cations in different atomic sites of TB structure plays a vital role in tailoring the physical and electrical properties of the materials for device applications.…”

Electrical and magnetic properties of 0–3 Ba(Fe1∕2Nb1∕2)O3/PVDF composites

“…Further, " 0 -f plots for BFN find maxima after 200 C, which shift towards lower frequency side with increasing temperature, assumably due to the resonance effect. 24 The precise prediction of the filler concentrationdependent effective relative permittivity (" The formulae used in the present investigation are as follows:…”

“…In addition, tailoring of their properties can be done as per the requirement by changing the proportions of the constituents. Recently, a large number of ceramic/polymer-based 0-3 composites have been fabricated and studied with different aims such as: BaTiO 3 /PVDF, [6][7][8][9] 11 for embedded capacitor applications and to understand the carrier transport mechanism; Ba 0:5 Sr 0:5 TiO 3 /P(VDF-CTFE) 12 for energy storage applications; (Bi 0:5 Na 0:5 Þ 0:94 Ba 0:06 TiO 3 /P(VDFTrFE) 13 to view the combined effect of segmental chain relaxation in polymer phase and dipole relaxation in ceramic phase; BCT-BZT/P(VDF-TrFE) 14 and (Bi 0:5 Na 0:5 Þ 0:94 Ba 0:06 -TiO 3 /PVDF 15 for piezoelectric, pyroelectric applications; Pb(Zr,Ti)O 3 /PVDF 16 toward utilization of dielectric, ferroelectric, piezoelectric, pyroelectric, electrooptic and superconducting properties in micro-devices; CaCu 3 [22][23][24][25][26][27][28] while polyvenylidene fluoride (PVDF) is one of the most effective low-cost polymers having low complex permittivity and low thermal conductivity. It would not be out of place to mention here that both the constituents of the above-referred ceramic/polymer composite are environment-friendly.…”