TY  - JOUR
AU  - Androš Dubraja, Lidija
AU  - Kruk, Robert
AU  - Brezesinski, Torsten
TI  - Robust Macroscopic Polarization of Block Copolymer-Templated Mesoporous Perovskite-Type Thin-Film Ferroelectrics
JO  - Advanced electronic materials
VL  - 5
IS  - 1
SN  - 2199-160X
CY  - Chichester
PB  - Wiley
M1  - PUBDB-2019-00716
SP  - 1800287
PY  - 2019
N1  - © WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
AB  - Ferroelectrics play an important role in various applications, from electronics to mechanics, optics, and biomedicine. Here, the preparation of a series of block copolymer–templated mesostructured (lead‐free) oxide ferroelectrics is described. Distorted perovskite LiNbO<sub>3</sub>, LiTaO<sub>3</sub>, and solid solution LiNbO<sub>3</sub>–LiTaO<sub>3</sub> are produced as single‐phase thin films of good quality by the dip‐coating method using an evaporation‐induced self‐assembly process. They are investigated by a combination of electron microscopy, X‐ray diffraction and scattering, X‐ray photoelectron spectroscopy, and time‐of‐flight secondary ion mass spectrometry. Thermal treatment at ≥600 °C is required to initiate crystallization. Both the pore ordering and thermal stability increase with increasing tantalum content. Ferroelectric testing through dynamic and remanent polarization experiments at ambient conditions confirm the uniformity and purity of the LiNbO<sub>3</sub> thin‐film system. Results from positive‐up and negative‐down test measurements reveal a stable switching polarization of 2 µC cm<sup>−2</sup>, with a coercive field of 50 kV cm<sup>−1</sup>. Taken together, the lithium niobium and tantalum oxides prepared in the work are rare examples of sol–gel derived perovskite‐type materials with an ordered mesoporous morphology. Because of the spontaneous electrical polarization observed for LiNbO<sub>3</sub>, such block copolymer–templated thin films might pave the way for the development of a new class of 3D nanocomposite ferroics.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000455220900020
DO  - DOI:10.1002/aelm.201800287
UR  - https://bib-pubdb1.desy.de/record/418800
ER  -