Empirical Models for Layered A‐Site Ordering in Perovskite Titanates

Authors

Evan Smith, Boise State University
Rick Ubic, Boise State UniversityFollow

Document Type

Article

Publication Date

5-2019

Abstract

In industry and labs, predictive models describing processing‐structure relationships are inherently valuable, yet few exist for cation ordering in perovskites. In this work, 15 compositions in the [(Na_yLi_1−y)_(1−3x)/2La_(1+x)/2]TiO₃ (NLLT) system (y = 0.25, 0.5, and 0.75; x = 0, 0.0533, 0.1, 0.1733, and 0.225) were synthesized using a conventional solid‐state mixed‐oxide method. X‐ray diffraction data show that some degree of long‐range ordering of A‐site cations exists for x ≥ 0.1, although electron‐diffraction data indicate that short‐range ordering exists even for x < 0.1, with the degree of ordering decreasing as the value of x increases. Empirical models have been derived for the A‐site ordering parameter (η) as well as the resultant expansion (Δr_A) for each y series in the NLLT system, from which two general models were derived for perovskites with any arbitrary degree of 1:1 layered A‐site ordering. These general models allow for the prediction of the order parameter and resulting expansion using only published ionic radii data.

Publication Information

Smith, Evan and Ubic, Rick. (2019). "Empirical Models for Layered A‐Site Ordering in Perovskite Titanates". Journal of the American Ceramic Society, 102(5), 3019-3031. https://doi.org/10.1111/jace.16168