Polar order and diffuse scatter in Ba(Ti1−xZrx)O3 ceramics

Abstract

The Ba(Ti1−xZrx)O3 (BTZ) system with x≤0.35 has been studied using a combination of x-ray diffraction, dielectric measurements, Raman spectroscopy, and electron diffraction with a view to better understand the changes in structure and correlation length of polar order as a function of composition and temperature. Careful fitting of Raman spectra has confirmed stabilization of the orthorhombic phase at room temperature in x=0.05 with mixed phase (orthorhombic and rhombohedral) present at 80 K. Raman data suggest that the rhombohedral phase is most likely to be present at low temperature for x=0.15 and 0.25 and that only short range polar order evolves in x=0.35. Interpretation of the Raman spectra is in broad agreement with the dielectric data as a function of composition and temperature. Diffuse scatter at room temperature in high order zone axis electron diffraction remains essentially identical for all compositions irrespective of structure and correlation length of polar order. The diffuse maxima are therefore considered not to relate directly to the correlation length of polar order in the BTZ system and therefore do not contribute to the dielectric behavior.

Growth and characterization of lead-free Ba(1−x)CaxTi(1−y)ZryO3 single crystal

“…However, it is hard to distinguish any other phase transition from the present Raman spectra. It should be noted that the tendency and some features of the Raman spectra are similar to previous results [25,26].…”

PbMg1/3Nb2/3O3-doping effects on structural, thermal, Raman, dielectric and ferroelectric properties of BaTiO3 ceramics

“…Three broad bands at 272 cm −1 and 520 cm −1 are attributed to the A 1 (LO) mode. Similar bands were observed in BT ceramic by Farhi et al 14 and by Miao et al 16 Raman spectra of PMN consist of number of broad, overlapping lines. As room temperature is far below T d temperature, these Raman spectra appear mainly due to presence of nanoregions with rhombohedral symmetry (R3m).…”

Static and dynamic polar nanoregions in relaxor ferroelectric Ba(Ti1−xSnx)O3Xie1, Li2, Yu3 et al. 2012Phys. Rev. B782260View full textAdd to dashboardCite

“…As a result, the electron diffraction diffuse scatterings remain essentially identical irrespective of the composition and the structure. 9,22,23 Also, the size of these static PNRs is too small to be probed by the piezoresponse force microscopy method, and as a result, their piezoactivity could not be observed. 24 The possible mechanism for the static PNRs formation can be the result of local composition fluctuations, which act as sites to quench local polar structures and where a local phase transition takes place.…”

“…9,22 This suggests that the correlation length of PNRs is almost unchanged in both the ferroelectrics and the relaxors. 23 In contrast, a complex domain structure with an average domain size of 100 × 100 nm 2 in the ferroelectric BTSn was reported by using the piezoresponse force microscopy, 24 but no piezoactivity could be found in the relaxor BTSn. 24 To fully understand the PNRs, structural disorder, and their relation to the relaxor behavior in the lead-free relaxors, we carried out structure characterizations of Ba(Ti 1−x Sn x )O 3 at ambient temperature by means of conventional dark field imaging and aberration-corrected high-resolution transmission electron microscopy.…”