Video Experimental Relacionado

Updated: Jul 2, 2025

Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals

Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals

Published on: August 15, 2018

Actuación anisotrópica a temperatura ambiente impulsada por una transición de fase sinérgica de orden y desorden en

Ming-Liang Jin¹, Xiang-Bin Han¹, Cheng-Dong Liu¹

¹Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics and School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China.

Journal of the American Chemical Society

|February 21, 2024

Resumen

Los investigadores desarrollaron un nuevo cristal ferroeléctrico, (rac-3-HOPD) PbI3, que exhibe cambios significativos en la forma a temperatura ambiente. Este material ofrece una nueva vía para crear materiales de accionamiento avanzados con propiedades únicas.

Área de la Ciencia:

Ciencias de los materiales
La cristalografía
Ferroelectricidad

Sus antecedentes:

Los materiales de accionamiento son cruciales para convertir la energía en respuestas mecánicas.
Existe una demanda de materiales de accionamiento con grandes cambios de forma reversibles y nuevas funcionalidades.

Objetivo del estudio:

Para reportar un nuevo cristal ferroeléctrico con comportamientos de accionamiento grandes y anisotrópicos a temperatura ambiente.
Para explorar las relaciones estructura-propiedad que impulsan estos comportamientos actuadores.

Principales métodos:

Síntesis y caracterización del cristal ferroeléctrico (rac-3-HOPD) PbI3.
Investigación de las transiciones de fase y su correlación con los cambios de forma mediante análisis cristalográfico.
Fabricación y ensayo de prototipos de dispositivos.

Principales resultados:

El cristal exhibe cambios de forma gigantescos y anisotrópicos (+ 24,6% a lo largo del eje b, -17,5% a lo largo del eje c) impulsados por una transición de fase ferroeléctrica cerca de la temperatura ambiente.
La estructura cristalina única, con cadenas aniónicas [PbI3] y cationes en forma de disco, facilita estas grandes transformaciones de celosía.
Se demostraron con éxito los prototipos de interruptores de circuito y ascensores utilizando el accionamiento dependiente de la temperatura negativa del material.

Conclusiones:

El cristal ferroeléctrico (rac-3-HOPD) PbI3 presenta un nuevo modelo para materiales mecánicamente sensibles.
El mecanismo sinérgico de orden-desorden y transición de fase de desplazamiento permite propiedades de accionamiento significativas.
Este descubrimiento abre caminos para el desarrollo de materiales multifuncionales para diversas aplicaciones.

Más Videos Relacionados

Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope

Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope

Published on: March 24, 2019

Preparation of Liquid Crystal Networks for Macroscopic Oscillatory Motion Induced by Light

Preparation of Liquid Crystal Networks for Macroscopic Oscillatory Motion Induced by Light

Published on: September 20, 2017

Videos de Conceptos Relacionados

Ferromagnetism

Ferromagnetism

Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...

Dielectric Polarization in a Capacitor

Dielectric Polarization in a Capacitor

The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...

Crystal Field Theory - Octahedral Complexes

Crystal Field Theory - Octahedral Complexes

Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...

Crystal Field Theory - Tetrahedral and Square Planar Complexes

Crystal Field Theory - Tetrahedral and Square Planar Complexes

Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...