Video Experimental Relacionado
Updated: May 21, 2026
07:03
Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
Ferroelectricidad inducida por el ordenamiento del movimiento de torsión en un rotor molecular
Yi Zhang1, Wen Zhang, Shen-Hui Li
1Ordered Matter Science Research Center, Southeast University, Nanjing 211189, P. R. China.
Journal of the American Chemical Society
|June 13, 2012
Resumen
Un nuevo compuesto metalo-orgánico exhibe una transición de fase de paraeléctrico a ferroeléctrico a 235 K, impulsado por la dinámica del rotor molecular. Los estudios de deuteración confirmaron que el ordenamiento de protones no es la causa de la ferroelectricidad.
Área de la Ciencia:
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- Química del estado sólido.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- Los compuestos orgánicos metálicos ofrecen propiedades sintonizables para aplicaciones avanzadas.
- Comprender la dinámica molecular es crucial para el diseño de materiales funcionales.
Objetivo del estudio:
- Para sintetizar y caracterizar un nuevo compuesto orgánico-metálico mononuclear, [Cu(Hdabco)(H(2)O)Cl(3)].
- Para investigar su transición de fase paraeléctrica a ferroeléctrica y sus comportamientos dinámicos.
Principales métodos:
- Un solo cristal de difracción de rayos X de un solo cristal.
- El análisis térmico (DSC/TGA)
- Las mediciones dieléctricas y ferroeléctricas.
- Experimentos de segunda generación armónica (SHG)
- Espectroscopia de resonancia magnética nuclear (RMN) en estado sólido.
Principales resultados:
- El compuesto exhibe una transición de fase a 235 K (T ((c)).
- Por encima de la temperatura ambiente, funciona como un rotor molecular con la porción (Hdabco) girando.
- Se observó un movimiento de torsión del rotador entre 235 y 301 K.
- La ferroelectricidad por debajo de T (c) se atribuye a los arreglos moleculares ordenados y a los desplazamientos catión/anión.
Conclusiones:
- El compuesto sintetizado muestra un comportamiento único de conmutación paraeléctrica a ferroeléctrica.
- La dinámica del rotor molecular influye significativamente en las propiedades ferroeléctricas observadas.
- El ordenamiento de protones no es el origen de la ferroelectricidad, como lo demuestran los estudios sobre el análogo deuterado.
Más Videos Relacionados
Videos de Conceptos Relacionados
01:28Induced Electric Dipoles
A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
01:31Ferromagnetism
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...
01:22Motional Emf
Magnetic flux depends on three factors: the strength of the magnetic field, the area through which the field lines pass, and the field's orientation with respect to the surface area. If any of these quantities vary, a corresponding variation in magnetic flux occurs. If the area through which the magnetic field lines are passing changes, then the magnetic flux also changes. This change in the area can be of two types: the flux through the rectangular loop increases as it moves into the magnetic...
01:23Magnetic Field due to Moving Charges
A stationary charge creates and interacts with the electric field, while a moving charge creates a magnetic field.
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
01:31Dielectric 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...
01:27π Electron Effects on Chemical Shift: Overview
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0, resulting in...