X-ray diffuse scattering observations for Sr_xBa_1−xNb₂O₆ single crystals with x=0.35 and 0.81

ABSTRACT

In an attempt to contribute to understanding of structure–property relationship in ferroelectric relaxor Sr${}_x$Ba${}_{1-x}$Nb${}_2$O${}_6$, we studied X-ray diffuse scattering for compositions with x = 0.35 and x = 0.81 at room temperature. Within signal-rich reciprocal-space images, features related to (i) local deformation due to chemical inhomogeneity, (ii) incommensurate modulation and (iii) fluctuation of polarization have been identified. There are substantial differences between the two compositions, some of which can be straightforwardly attributed to different states of ferroelectric ordering in these materials. In the Sr-rich composition, we have observed additional features in the form of $⟨110⟩$-oriented streaks on $hk\left(n/2\right)$ planes. They indicate that transverse correlation of uniaxial polarization is anisotropic. At the same time, the fact that streaks appear also on the superlattice planes raises the question whether the modulation and polarization order parameter are interrelated.

KEYWORDS:

• Relaxor ferroelectrics
• disorder
• diffuse scattering

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

M. Paściak http://orcid.org/0000-0002-3902-8874

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the Czech Science Foundation (Grantová Agentura České Republiky) (project No. 16-09142S). The research leading to this result has been supported by the project CALIPSOplus under Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020.