Origin of microcracking in YMnO3 ceramics

authors	Tomczyk, M; Senos, AM; Vilarinho, PM; Reaney, IM
nationality	International
journal	SCRIPTA MATERIALIA
author keywords	YMnO3; Multiferroic; Ceramics; Microcracking
keywords	THERMAL-EXPANSION ANISOTROPY; TITANATE-MULLITE COMPOSITES; MANGANITES; BEHAVIOR; GEL
abstract	YMnO3 is a multiferroic with a high-temperature ferroelectric phase transition (T-C = 913 K) and a subambient Neel temperature (T-N = 70 K). Ferroelectricity has been reported for single crystals and epitaxial thin films but to date not for ceramics. We postulate that the absence of direct evidence of ferroelectricity in ceramic YMnO3 might be attributed to microcrack formation (3.2 vol.%) on cooling. We show that microcracking originates from a combination of 3.7 vol.% change and strong anisotropy in the thermal expansion coefficient (a) of the hexagonal structure (alpha(a)-alpha(c)vertical bar approximate to 4.57 x 10(-5)degrees C-1) between 600 and 1000 degrees C. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
publisher	PERGAMON-ELSEVIER SCIENCE LTD
issn	1359-6462
year published	2012
volume	66
issue	5
beginning page	288
ending page	291
digital object identifier (doi)	10.1016/j.scriptamat.2011.11.014
web of science category	Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering
subject category	Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering
unique article identifier	WOS:000300129200023