Premium
Structural and Raman study of the thermoelectric solid solution Sr 1.9 La 0.1 Nb 2 O 7
Author(s) -
OjedaGalván Hiram Joazet,
RodríguezAranda Ma. del Carmen,
Rodríguez Ángel Gabriel,
Alanis Javier,
Íñiguez Jorge,
Mendoza María Eugenia,
NavarroContreras Hugo Ricardo
Publication year - 2021
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.6032
Subject(s) - raman spectroscopy , thermoelectric effect , crystallite , ambient pressure , materials science , analytical chemistry (journal) , phase transition , solid solution , density functional theory , ceramic , phonon , phase (matter) , mineralogy , condensed matter physics , chemistry , thermodynamics , metallurgy , computational chemistry , physics , organic chemistry , chromatography , optics
Ceramic powder samples of the perovskite‐slab‐layered polycrystalline Sr 1.9 La 0.1 Nb 2 O 7 (SLNO1) thermoelectric solid solution were prepared via solid‐state reaction. The Raman effect was studied as a function of temperature between 27°C and 400°C (at ambient pressure) and pressures up to 11.6 GPa (at room temperature). The atomic disorder introduced by the La atoms produced phonon lines that were broader than those of Sr 2 Nb 2 O 7 (SNO). We detected a temperature‐induced phase transition at T i−c = 247 ± 5°C (ambient pressure) and a pressure‐induced phase transition at P i−c = 6.74 ± 0.25 GPa (room temperature), which correspond to the reported SNO incommensurate‐to‐commensurate phase transitions at 215°C (atmospheric pressure) and P i−c = 6.54 ± 0.25 GPa (27°C), respectively. In this paper, the phenomenological and structural differences between SNO and SLNO1 are discussed based on density functional theory calculations of Sr 2−x La x Nb 2 O 7 ( x = 0.0625 and 0.125) supercells.