Abstract: Quinuclidinium salts and their derivatives are now in the focus of materials science as building units of
multifunctional materials. Their properties can be easily switchable, allowing their use in a wide range of
physical applications. One type of these kinds of materials, the homochiral hybrid halometallate
ferroelectric compounds, is not well understood. In this work, (R)-()-3-quinuclidinol hydrochloride was
used in the synthesis of ((R)-()-3-hydroxyquinuclidium)[FeCl4]. The use of this enantiomeric cation forces
crystallographic non-centrosymmetry, which was confirmed by polarimetry and circular dichroism
spectroscopy. We studied the physical properties of this compound at different temperatures by single
crystal, synchrotron and neutron powder X-ray diffraction, which showed a rich series of structural and
magnetic phase transitions. From synchrotron powder X-ray diffraction data, a plastic phase was observed
above 370 K (phase I). Between 370 K and ca. 310 K, an intermediate polar phase was detected, solved in
a non-centrosymmetric polar space group (C2) (phase II). Below ca. 310 K, the compound crystallizes in
the triclinic P1 non-centrosymmetric space group (phase III) which is maintained down to 4 K, followed by
phase IV, which shows tridimensional magnetic ordering. The temperature evolution of the neutron
diffraction data shows the appearance of new reflections below 4 K. These reflections can be indexed to a
commensurate propagation vector k = (0, 0, 12). The magnetic structure below TN was solved in the Ps1
Shubnikov space group, which gives rise to an antiferromagnetic structure, compatible with the
magnetometry measurements. Near room temperature, the crystal phase transition is associated with a
dielectric change. In particular, the phase transition between phase III (S.G.:P1) and phase II (S.G.:C2)
involves an increase of symmetry between two non-centrosymmetric space groups. Therefore, it allows,
by symmetry, the emergence of ferroelectric and ferroelastic ordering. Piezoresponse force microscopy
(PFM) imaging measurements provided evidence for polarization switching and a local ferroelectric
behavior of phase III at room temperature. Additionally, the obtained butterfly curve and hysteresis loop by
PFM exhibits a low coercive voltage of B10 V. This value is remarkable, since it approaches those
obtained for materials with application in ferroelectric random access memories (FeRAMs).
Otras publicaciones de la misma revista o congreso con autores/as de la Universidad de Cantabria
Fuente: Journal of Materials Chemistry C, volume 9 (2021), Issue 13, páginas 4453-4465
Editorial: Royal Society of Chemistry
Fecha de publicación: 07/04/2021
Nº de páginas: 13
Tipo de publicación: Artículo de Revista
DOI: 10.1039/D0TC05800A
ISSN: 2050-7526,2050-7534
Proyecto español: MAT2017-89239-C2-(1,2)-P ; MAT2017-83631-C3-3-R
Url de la publicación: https://doi.org/10.1039/D0TC05800A