Video Experimental Relacionado
Updated: Jul 15, 2026
14:13
Atomic Force Microscopy of Red-Light Photoreceptors Using PeakForce Quantitative Nanomechanical Property Mapping
Published on: October 24, 2014
Observación directa de la percolación en una película delgada de manganito
Liuwan Zhang1, Casey Israel, Amlan Biswas
1Department of Physics, University of Texas, Austin, TX 78712, USA.
Science (New York, N.Y.)
|September 21, 2002
Resumen
Los dominios ferromagnéticos en las películas LaPrCaMnO3 crecen al enfriarse pero no al calentarse, causando cambios en la resistividad. Esta inhomogeneidad magnética explica las propiedades de magnetorresistencia del material.
Área de la Ciencia:
- Física de la materia condensada Física de la materia condensada
- Ciencia de los materiales Ciencia de los materiales.
- El magnetismo es el magnetismo.
Sus antecedentes:
- La0.33Pr0.34Ca0.33MnO3 exhibe complejas propiedades magnéticas y electrónicas.
- Comprender la dinámica del dominio es crucial para explicar la magnetorresistencia en las manganitas de perovskita.
Objetivo del estudio:
- Para investigar el comportamiento dependiente de la temperatura de los dominios ferromagnéticos en películas delgadas La0.33Pr0.34Ca0.33MnO3.
- Para correlacionar el crecimiento del dominio y las propiedades magnéticas con los cambios de resistividad y magnetorresistencia.
Principales métodos:
- Medidas de resistividad a través de las transiciones metal-aislador.
- Imágenes y análisis del dominio magnético durante los ciclos de enfriamiento y calentamiento.
Principales resultados:
- Los dominios ferromagnéticos crecen al enfriarse a la temperatura de transición metal-aislador (TP1) y por debajo, mientras que permanecen estáticos durante el calentamiento hasta cerca de TP1.1.
- Una disminución en la magnetización promedio se correlaciona con saltos de resistividad.
- Se observan histeresis magnética local e inhomogeneidad, con algunos dominios que persisten por encima de TP2.2.
Conclusiones:
- La dinámica del dominio observado y la inhomogeneidad magnética son clave para comprender la magnetorresistencia en La0.33Pr0.34Ca0.33MnO3.3.
- El crecimiento asimétrico del dominio durante el enfriamiento versus el calentamiento contribuye a la histeresis de la resistividad.
Videos de Conceptos Relacionados
01:18Rise of Liquid in a Capillary Tube
When very thin cylindrical tubes, called capillaries, are dipped in a liquid, the liquid rises or falls in the tube compared to the surrounding liquid. This phenomenon is called capillary action. Capillary action occurs due to the combination of two opposing forces: the cohesive forces of the liquid, which cause it to stick to itself and form a rounded shape, and the adhesive forces between the liquid and the walls of the container, which cause the liquid to be attracted to the container walls.
01:19Capillarity in Fluid
Capillarity describes the movement of liquid in small spaces without external forces acting on it. The capillarity is driven by surface tension and adhesive interactions between the liquid and surrounding solid surfaces. This effect is often seen in narrow tubes, porous materials, and fine particles.
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...
01:17Steady, Laminar Flow Between Parallel Plates
Understanding steady, laminar flow between parallel plates is essential for analyzing and designing flow in narrow rectangular channels, commonly found in various water conveyance and drainage systems. The Navier-Stokes equations govern fluid motion and are generally challenging to solve due to their nonlinearity. However, simplifications are possible in certain cases, like the steady laminar flow between parallel plates. For this scenario, we assume steady, incompressible, laminar flow.
01:23Steady, Laminar Flow in Circular Tubes
Hagen-Poiseuille flow describes a viscous fluid's steady, incompressible flow through a cylindrical tube with a constant radius R. This flow profile is often applied to understand fluid transport in narrow channels, such as capillaries. It serves as a foundational example of laminar flow. In this model, cylindrical coordinates (r,θ,z) are used to describe the radial (r), angular (θ), and axial (z) dimensions within the tube. For Hagen-Poiseuille flow, the velocity profile is purely axial,...