直接观察矿薄膜中透的情况
Liuwan Zhang1, Casey Israel, Amlan Biswas
1Department of Physics, University of Texas, Austin, TX 78712, USA.
Science (New York, N.Y.)
|September 21, 2002
概括
在LaPrCaMnO3膜中的铁磁域在冷却时增长,但没有变暖,导致电阻变化. 这种磁性不均性解释了材料的磁电阻特性.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学 材料科学 材料科学
- 磁力学 磁力学 是一种
背景情况:
- La0.33Pr0.34Ca0.33MnO3 具有复杂的磁性和电子性质.
- 了解域动力学对于解释矿矿中的磁电阻至关重要.
研究的目的:
- 为了研究铁磁域在La0.33Pr0.34Ca0.33MnO3薄膜中的温度依赖性行为.
- 为了将域增长和磁性与电阻变化和磁阻变化相关联.
主要方法:
- 跨金属绝缘体过渡的电阻测量.
- 在冷却和变暖周期期间对磁域进行成像和分析.
主要成果:
- 铁磁域在金属绝缘体过渡温度 (TP1) 和以下冷却时增长,而在加热期间保持静态,直到接近TP1.1.
- 平均磁化率的下降与电阻率的跳跃有关.
- 观察到局部磁性歇斯底里和不均性,一些域持续在TP2.2以上.
结论:
- 观察到的域动态和磁性不均性是理解La0.33Pr0.34Ca0.33MnO3.3中的磁阻的关键.
- 在冷却和变暖期间不对称的域增长有助于电阻性歇斯底里.
相关概念视频
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,...