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Stability and Decomposition of Perovskite‐Type Titanates upon High‐Temperature Reduction (Phys. Status Solidi RRL 9/2017)
Author(s) -
Rodenbücher Christian,
Meuffels Paul,
Speier Wolfgang,
Ermrich Martin,
Wrana Dominik,
Krok Franciszek,
Szot Kristof
Publication year - 2017
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201770345
Subject(s) - strontium titanate , oxide , sublimation (psychology) , nanocrystalline material , getter , materials science , annealing (glass) , perovskite (structure) , metal , chemical engineering , chemistry , nanotechnology , metallurgy , thin film , crystallography , optoelectronics , psychology , engineering , psychotherapist
Perovskite‐type oxides such as strontium titanate (SrTiO 3 ) are the key materials for future energy‐efficient information and energy technology due to their extraordinary properties. A frequently employed method to tailor those properties is thermal reduction under vacuum conditions whereupon the oxide gains metallic properties due to the release of oxygen. The question now arises: What else could happen in course of thermal reduction? In order to investigate this question, Rodenbücher et al. (article no. 1700222 ) have performed thermal annealing experiments under different conditions. It is shown that under standard vacuum conditions the oxide is macroscopically stable and changes its electronic properties without a significant structural transformation. However, as soon as a material with high oxygen affinity such as Ti acting as oxygen getter is placed in the vicinity of the oxide during vacuum annealing, an evaporation of Sr sets in and a porous surface layer consisting of titanium suboxides in nanocrystalline form evolves. This surprising behaviour can be understood as an incongruent sublimation of the alkaline earth metal (here Sr) taking place at extremely low oxygen partial pressures.