La contracción del volumen colosal en las perovskitas polares fuertes de Pb
Zhao Pan1,2,3, Jun Chen1,3, Xingxing Jiang4
1Department of Physical Chemistry, University of Science and Technology Beijing , Beijing 100083, China.
Journal of the American Chemical Society
|October 11, 2017
Resumen
Los investigadores mejoraron la expansión térmica negativa (NTE) en materiales de titanato de plomo mediante la sustitución de vanadio. Este estudio logró una contracción de volumen gigante, ofreciendo una nueva ruta para el desarrollo de materiales NTE avanzados.
Área de la Ciencia:
- Ciencias de los materiales
- Física del estado sólido
- La cristalografía
Sus antecedentes:
- La expansión térmica negativa (NTE) es una propiedad física única con implicaciones científicas y prácticas significativas.
- Mejorar la NTE en los materiales existentes es un desafío, ya que las modificaciones químicas a menudo debilitan esta propiedad.
- El desarrollo de materiales con NTE mejorado es crucial para aplicaciones tecnológicas avanzadas.
Objetivo del estudio:
- Para lograr una mayor expansión térmica negativa (NTE) en materiales a base de titanato de plomo (PbTiO3).
- Investigar el efecto de la sustitución del vanadio en las propiedades de expansión ferroeléctrica y térmica del PbTiO3.
- Explorar un nuevo enfoque para el diseño de materiales con NTE significativos.
Principales métodos:
- Sustitución química del vanadio (V) en la red de titanato de plomo (PbTiO3) para formar Pb{\displaystyle Pb{\mathrm {Ti} }1-xVx}O3.
- Cálculos de primeros principios para analizar los cambios en la estructura de la celosía, la polarización y el enlace.
- Caracterización experimental de las propiedades de expansión térmica en un amplio rango de temperaturas.
Principales resultados:
- La sustitución de vanadio promovió significativamente la tetragonalidad de la celosía (c/a) en Pb(Ti1-xVx) O3, relacionada con una mayor polarización espontánea y enlace covalente.
- Pb{Ti0.9V0.1) O3 demostró un NTE no lineal significativamente más fuerte con un coeficiente volumétrico de expansión térmica αV = -3.76 × 10^-5 / °C (25-550 °C).
- Se observó una contracción de volumen gigante intrínseca de ~ 3,7% en Pb ((Ti0.7V0.3) O3 durante la transición de fase ferroeléctrica a paraeléctrica, atribuida a la ferroelectrostricción de volumen espontánea.
Conclusiones:
- El estudio logró con éxito una NTE mejorada en Pb ((Ti1-xVx) O3 mediante el aprovechamiento de las propiedades ferroeléctricas.
- Los hallazgos demuestran una estrategia eficaz para explorar nuevos materiales NTE ajustando las características ferroeléctricas.
- Este trabajo amplía la familia de materiales NTE y ofrece una vía para el desarrollo de materiales con grandes cambios de volumen controlables.
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