View in EDS

Cation substitution–induced structural disorder in titanate pyrochlores: A multi-spectroscopic study.

Saved in:
Bibliographic Details
Title: Cation substitution–induced structural disorder in titanate pyrochlores: A multi-spectroscopic study.
Authors: Esfahani, Maryam Hasanzadeh1 (AUTHOR), Naji, Hojjat2 (AUTHOR), Greedan, John3 (AUTHOR), Behzad, Mahdi1 (AUTHOR) mahdibehzad@gmail.com
Source: Ceramics International. Jul2026, Vol. 52 Issue 17, p31928-31935. 8p.
Subjects: Pyrochlore, Crystal lattices, Spectrum analysis, Rare earth oxides, X-ray diffraction, Raman spectroscopy, Metal ions, Crystal structure
Abstract: Rare-earth titanate pyrochlores are known for their structural sensitivity to A-site cation composition, where even subtle changes in stoichiometry can influence lattice parameters and local structural ordering. In this work, we investigated the effect of slight compositional variation in Dy x Sm 2-x Ti 2 O 7 (x = 0.6–1.4) pyrochlores to assess how small changes in A-site occupancy affect the overall crystal structure. High-purity ceramics were synthesized via a modified solid-state reaction route. The structural and microstructural characteristics were examined using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM). XRD analysis confirmed the formation of the pyrochlore phase across the studied composition range, accompanied by systematic but subtle shifts in diffraction peak positions and a gradual decrease in lattice parameters with increasing Dy3+ content, consistent with lattice contraction induced by ionic size mismatch. In contrast, Raman and FT-IR spectra exhibited only minor variations, indicating that local vibrational features were less sensitive to such slight compositional changes. SEM observations revealed modest microstructural evolution with composition. Overall, the results demonstrated that even small variations in A-site cation composition could measurably influence the crystal lattice of pyrochlore titanates, primarily reflected in long-range structural parameters rather than pronounced changes in local vibrational spectra. [ABSTRACT FROM AUTHOR]
Copyright of Ceramics International is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:Rare-earth titanate pyrochlores are known for their structural sensitivity to A-site cation composition, where even subtle changes in stoichiometry can influence lattice parameters and local structural ordering. In this work, we investigated the effect of slight compositional variation in Dy x Sm 2-x Ti 2 O 7 (x = 0.6–1.4) pyrochlores to assess how small changes in A-site occupancy affect the overall crystal structure. High-purity ceramics were synthesized via a modified solid-state reaction route. The structural and microstructural characteristics were examined using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM). XRD analysis confirmed the formation of the pyrochlore phase across the studied composition range, accompanied by systematic but subtle shifts in diffraction peak positions and a gradual decrease in lattice parameters with increasing Dy3+ content, consistent with lattice contraction induced by ionic size mismatch. In contrast, Raman and FT-IR spectra exhibited only minor variations, indicating that local vibrational features were less sensitive to such slight compositional changes. SEM observations revealed modest microstructural evolution with composition. Overall, the results demonstrated that even small variations in A-site cation composition could measurably influence the crystal lattice of pyrochlore titanates, primarily reflected in long-range structural parameters rather than pronounced changes in local vibrational spectra. [ABSTRACT FROM AUTHOR]
ISSN:02728842
DOI:10.1016/j.ceramint.2026.05.235