Supramolecular systems hold great potential as ferroelectric materials because they are easy to prepare and do not require toxic and environmentally damaging elements. However, directing the self-assembly process of a supramolecular array to yield polarizable solids is still challenging. Here, we describe induced ferroelectricity in a supramolecular framework of metal-organic cages that are supported by a flexible tripodal ligand (NHCH -(3-Py)) PO (TPPA). Ferroelectric responses on the discrete cage [Cu (H O) (TPPA) ](NO ) ⋅ 45H O (1) and its 2D-connected framework [{Cu Cl (H O) (TPPA) }(NO ) ⋅ 60H O] (2) yielded well-resolved rectangular hysteresis loops at room temperature with remnant polarization values of 27.27 and 29.09 μC/cm , respectively. Thermal hysteresis measurements (THM) and capacitance-voltage (C-V) plots further corroborate the ferroelectric behavior in these compounds. The polarization in them is due to the displacements of solvated molecules and nitrate ions in the pockets of these frameworks.
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http://dx.doi.org/10.1002/asia.202000744 | DOI Listing |
Nat Commun
January 2025
Key Laboratory of Polar Materials and Devices (Ministry of Education), Shanghai Center of Brain-Inspired Intelligent Materials and Devices, Department of Electronics, East China Normal University, Shanghai, 200241, China.
Moiré superlattices in two-dimensional stacks have attracted worldwide interest due to their unique electronic properties. A typical example is the moiré ferroelectricity, where adjacent moirés exhibit opposite spontaneous polarization that can be switched through interlayer sliding. However, in contrast to ideal regular ferroelectric moiré domains (equilateral triangles) built in most theoretical models, the unavoidable irregular moiré supercells (non-equilateral triangles) induced by external strain fields during the transfer process have been given less attention.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
Ferroelectric nematic (N) liquid crystals combine liquid-like fluidity and orientational order of conventional nematics with macroscopic electric polarization comparable in magnitude to solid-state ferroelectric materials. Here, we present a systematic study of twenty-seven homologous materials with various fluorination patterns, giving new insight into the molecular origins of spontaneous polar ordering in fluid ferroelectric nematics. Beyond our initial expectations, we find the highest stability of the N phase to be in materials with specific fluorination patterns rather than the maximal fluorination, which might be expected based on simple models.
View Article and Find Full Text PDFNano Lett
January 2025
Department of Electrical and Computer Engineering, The University of Texas at Dallas, Richardson, Texas 75080, United States.
Ferroelectric HfZrO (HZO) capacitors have been extensively explored for in-memory computing (IMC) applications due to their nonvolatility and back-end-of-line (BEOL) compatible process. Several IMC approaches using resistance and capacitance states in ferroelectric HZO have been proposed for vector-matrix multiplication (VMM), but previous approaches suffer from limited accuracy and reliability. In this work, we propose a promising approach centered on the remanent polarization (P) switching of binary ferroelectric HZO capacitor synapses.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
February 2025
Novosibirsk State University, Pirogova 1, Novosibirsk 630090, Russian Federation.
High-pressure and low-temperature structural changes in the ferroelectric phase of (R)-3-quinuclidinol are analysed. The changes in unit-cell volume and parameters are continuous both on cooling and under increasing pressure. The anisotropy of the structural strain, however, is found to be different.
View Article and Find Full Text PDFChem Sci
January 2025
Department of Chemistry, National Tsing Hua University Hsinchu 300044 Taiwan
PbZrTiO cubes with tunable sizes and cuboids have been hydrothermally synthesized. PbZrTiO cubes with three different Zr : Ti atomic percentages were also prepared. Analysis of synchrotron X-ray diffraction (XRD) patterns reveals the presence of two lattice components for these samples.
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