Publication Date:
2017-09-13
Description:
This work demonstrates the critical role of orbital hybridizations in the FeO 6 octahedral distortion, composition-driven phase transition, and bonding covalency in multiferroic (Bi 1- x Sm x )FeO 3 ( x =0.10-0.20) ceramics in the vicinity of the morphotropic phase boundary (MPB). Sequential composition-driven transitions from the polar rhombohedral R 3 c to antipolar orthorhombic Pbam and then Pnma phases were revealed as the system crosses the MPB with increasing Sm. A coexistence of ferroelectric (FE) rhombohedral R 3 c and antiferroelectric (AFE) PbZrO 3 -like orthorhombic Pbam symmetries was identified by the 1/2{000}, 1/4{000}, 1/4{110}, 1/4{111}, and 1/4{121}, superlattice diffractions at x =0.12-0.16. In addition to R 3 c and Pbam space groups, the nonpolar SmFeO 3 -like orthorhombic Pnma space group becomes the predominant phase at x =0.20 confirmed by the 1/2{100} superlattice diffractions. The Fe L 3 -edge and oxygen K-edge synchrotron X-ray absorptions indicate that the O 2 p –Fe 3 d and O 2 p –Bi 6 s /6 p orbital hybridizations were decreased as the system approaches the MPB. This article is protected by copyright. All rights reserved.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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