Ferroic phase transition molecular crystals

Abstract

Ferroic phase transition molecular crystals (FPTMCs), i.e., ferroelectrics and ferroelastics, are an important family of functional molecular materials, having merits of easy synthesis, structural tunability and flexibility, and biocompatibility. Both...

A three-dimensional Mn(ii) coordination polymer with ferroelasticity obtained by introducing coligands to form novel networks

“…1 Unlike other ferroic materials, ferroelastic materials undergo crystallographic morphological and/or structural changes and exhibit interesting mechanical properties when subjected to mechanical stress. [2][3][4][5][6][7][8] The study of ferroelastic materials has been of interest for decades because of their superior mechanical properties and their wide range of promising applications in superconductivity, superelasticity, non-linear optics, mechanical switching, and shape memory, and they also play an important role in the design of multiferroic devices. [9][10][11][12] After the discovery of Pb 3 (PO 4 ) 2 with full elastic hysteresis loops in 1976, numerous inorganic ferroelastic materials have been developed over the years, such as BaTiO 3 , BiFeO 3 , Bi 2 O 3 , BiVO 4 , VO 2 and others.…”

Large Phase-Transition Temperature Enhancement Achieved in a Layered Lead Iodide Hybrid Crystal by H/F Substitution

“…Organic–inorganic hybrid metal halides showing the impressive nature of solution processability and chemical modifications have attracted great attention and have been widely investigated to construct polyfunctional materials for potential applications in different scenarios. − Simultaneously, such cooperative hybrid systems with the integration of diversified organic motifs and inorganic frameworks also appear to be prime terraces for designing solid–solid phase-transition materials, which could undergo thermally triggered motions of the components to induce significant changes in physical performances, such as ferroelectricity and piezoelectricity. ,− The trend of high integration and miniaturization in smart devices often results in higher ambient temperatures; therefore, high phase-transition temperature ( T tr ) is essentially important for practical applications. , Despite the progress of phase-transition materials, those possessing high T tr remain few. The burning question still points to the most basic structure–property relationship to program desired functions.…”

Axial-Chiral BINOL Multiferroic Crystals with Coexistence of Ferroelectricity and Ferroelasticity

“…Interest in multiferroic materials that possess multiple ferroic orderings (i.e., spontaneous polarization, magnetization, or strain) has been long fervent, exhibiting great research importance and potential applications in a range of new multifunctional devices. − Among them, ferroelectricity and ferroelasticity are order parameters related to spatial symmetry, both of which are the result of symmetry breaking in structural phase transition . Ferroelectric materials with switchable spontaneous electric polarization must crystallize in 10 polar point groups, and the related symmetry changes should satisfy one of the 88 ferroelectric phase transitions derived by Aizu .…”

“…1−5 Among them, ferroelectricity and ferroelasticity are order parameters related to spatial symmetry, both of which are the result of symmetry breaking in structural phase transition. 6 Ferroelectric materials with switchable spontaneous electric polarization must crystallize in 10 polar point groups, and the related symmetry changes should satisfy one of the 88 ferroelectric phase transitions derived by Aizu. 7 Different from ferroelectrics, the spontaneous strain of ferroelastics originates from the exchange displacement of equivalent partial atomic pairs, which means that ferroelastic crystals require symmetry evolution for 94 ferroelastic transition types.…”