TY - JOUR A1 - Chen, Cong A1 - Müller, Bernd R. A1 - Lebedev, O. A1 - Giovannelli, F. A1 - Bruno, Giovanni A1 - Delorme, F. T1 - Effects of impurities on the stability of the low thermal conductivity in Fe2TiO5 ceramics T2 - Materials Characterization N2 - The stability of the low thermal conductivity in Fe2TiO5 pseudobrookite ceramics has been studied. An increase in thermal diffusivity is observed after only three cycles of measurement. X-ray refraction shows an increase in the mean value of specific surface after the thermal diffusivity measurements. By using scanning electron microscopy and high‐angle annular dark‐field scanning transmission electron microscope equipped with energy dispersive X-ray spectroscopy, we observe a segregation of Ca- and F-rich nanocrystals at grain boundaries after three cycles of thermal diffusivity measurement. Therefore, impurities seem to be more efficient to scatter phonons as point defects in the pseudobrookite lattice rather than as nanocrystals at pseudobrookite grain boundaries. This emphasizes the importance of precursor purity and the influence of redistribution of impurities on thermoelectric properties: stability of micro-/nano-structures is a key point, and repeated thermoelectric measurements may allow detecting such metastable micro- /nano-structures and producing stable and reliable data. PB - Elsevier Inc. KW - Fe2TiO5 KW - Impurity segregation KW - Thermoelectrics KW - X-ray refraction KW - Scanning transmission electron microscopy PY - 2019 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/47255 AN - OPUS4-47255 UR - http://www.sciencedirect.com/science/article/pii/S1044580318329309 SN - 1044-5803 SN - 1873-4189 VL - 149 SP - 111 EP - 117 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany