Dielectric Properties of RhombohedralPbNb2O6

Abstract

Dielectric materials are needed in many electrical and electronic applications. So, basic characterizations need to be done for all dielectrics. PbNb 2 O 6 (PN) is ferroelectric and piezoelectric only in its orthorhombic phase, with potential high temperature applications. So, its rhombohedral phase, frequently formed as an undesirable impurity in the preparation of orthorhombic PN, has been ignored with respect to possible dielectric characterizations. Here, essentially single phase rhombohedral PN has been prepared, checking structure from XRD Rietveld Analysis, and the real and imaginary parts of permittivity measured in an Impedance Spectrometer (IS) up to ∼ 700 ∘ C and over 20 Hz to 5.5 MHz range, for heating and some cooling runs. Variations, with temperature, of relaxation time constant ( ), AC and DC conductivity, bulk resistance, activation energy and capacitance have been explored from our IS data.

Effect of cadmium doping on electrical properties of lead nickel niobate–lead zirconate titanate [Pb1.0(Ni0.167Nb0.333Zr0.155Ti0.345)O3] ceramics

“…Fig. 5 shows that in the higher temperature region (4300 1C), Nyquist plots form single semicircular arcs in the studied frequency range, thereby suggesting the contribution from grains only [31,32]. The formation of one semicircular arc in the Nyquist plot is equivalent to a bulk resistance (R) and a capacitance (C) connected in parallel [31] which gives rise to dielectric relaxation time, τ¼ RC of the material.…”

Preparation, Structural, Electrical, and Ferroelectric Properties of Lead Niobate–Lead Zirconate–Lead Titanate Ternary System

“…Figure 2 shows the X-ray diffraction (XRD) patterns of three different compositions of PNZT, namely, PN-PZ-( -)PT (where = 0.5, = 0.15, 0.25, and 0.35) with a well-crystallized structure without the presence of pyrochlore or unwanted phases. The major diffraction peaks observed correspond to rhombohedral phase of PbNb 2 O 6 (JCPDS 29 -0780) with lattice parameters = 10.501, = = 90 ∘ , = 120 ∘ , and space group R3m (160) [15,29]. The peaks marked with star ( * ) in the figure correspond to PZT, thereby suggesting the presence of mixed phases in PNZT.…”

“…Niobium based perovskite oxides have attracted much attention because they show combined electrical and mechanical properties for use in the electronic industries [8][9][10]. In spite of the reports of an attractive high Curie temperature (517-570 ∘ C) [11,12], fewer studies [13][14][15] on PN have been carried out which can be attributed to the preparing of piezoelectric form (the metastable orthorhombic structure) in pure phase. On the other hand, one of the most widely studied ferroelectric materials due to its various potential technological applications is lead zirconate titanate, that is, PbZr 1− Ti O 3 (PZT) [16].…”

Ferroelectric Materials for High Temperature Piezoelectric Applications

“…Analysis[23,57,8] of ε(real) and ε(imaginary) data can yield rich information on electrical parameters or properties like capacitance, resistance and relaxation time of the equivalent CR circuit, dielectric loss (tanδ), AC and DC conductivities, and related activation energies. This area has been widely investigated by various authors[23,[59][60][61] for basic characterization of ferroelectric and piezoelectric materials. Study of the ferroelectric hysteresis loop of polarization P vs. electric field E as a function of temperature, outlined earlier, measures Remnant Polarization, P R in Fig.5(a), as well as Coercive Field, E C , and explores domain structure.…”