Relaxor behaviour of (Ba0·5Sr0·5)(Ti0·6Zr0·4)O3 ceramics

Abstract

Ba 0⋅5 Sr 0⋅5 Ti 0⋅6 Zr 0⋅4 O 3 ceramic has been prepared through solid state reaction route. X-ray diffraction shows that the sample has cubic perovskite structure with space group Pm-3m at room temperature. Temperature dependent dielectric study of the ceramic has been investigated in the frequency range 50 Hz-1 MHz. The density of the sample is determined using Archimedes' principle and is found to be ~99% of X-ray density. The dielectric study revealed diffuse phase transition of second order. A broad dielectric anomaly coupled with the shift of dielectric maxima toward a higher temperature with increasing frequency indicates the relaxor-type behaviour in the ceramics. The index of relaxation (γ) and the broadening parameter (Δ) were estimated from a linear fit of the modified Curie-Weiss law. The value of γ ~ 1⋅72 indicates the strong relaxor nature of the ceramic. A remarkably good fit to the Vogel-Fulcher relation further supports such a relaxor nature.

Optical and dielectric relaxor behaviour of Ba(Zr0.25Ti0.75)O3ceramic explained by means of distorted clusters

“…This value suggests that the material has structural order-disorder and diffuse phase transition. The observed broadness or diffusiveness occurs mainly because of the compositional fluctuation and/or due to the structural disorder into the lattice by the The slight deviations noted in the full width of the curves at different frequencies are analogous to those observed in other relaxor materials [67,68]. For a more detailed insight into the relaxation process in the relative dielectric permittivity, a graph of 1/T m was plotted as a function of ln(ν), as shown in figure 9.…”

Relaxor behavior in lead-free Ba(Ti1−xScx/2Nbx/2)O3 ceramics

“…One of the characteristics of the dipolar glass system as well as relaxor ferroelectrics is the appearance of a lowfrequency dielectric loss peak below T m . The loss peaks shift to lower frequencies on decreasing the temperature, indicating the thermally activated nature of the dielectric relaxation [29]. This phenomenon can be observed clearly for BT-BSN0.125 composition (Fig.…”

“…Moreover, to quantify frequency dispersion of T m (or relaxation degree), a parameter T m was defined by Eq. (4) [29]:…”

Stabilizing ferroelectricity in alkaline-earth-metal-based perovskites (ABO3) via A- (Ca2+/Sr2+/Ba2+) and B-site (Ti4+) cationic radius ratio (RA /RB )

“…6 that ST and BZ with cubic structure have nearly same Goldschmidt tolerance factor (t) with very different R A /R B . A-site doping with Sr, B-site doping with Zr, and A-and B-site doping with Sr and Zr, respectively, in BaTiO 3 give (Ba,Sr)TiO 3 (Garten et al, 2016), Ba(Ti,Zr)O 3 (Buscaglia et al, 2014) and (Ba,Sr)(Ti,Zr)O 3 (Badapanda et al, 2008). These solid solutions exhibit short-range ordering due to differences in the ionic radii of the host and dopant atoms, consequently leading to a relaxor ferroelectric nature (Garten et al, 2016;Buscaglia et al, 2014;Badapanda et al, 2008), which in turn modifies the physical response of the system.…”