Video Experimental Relacionado
Updated: Jul 5, 2026
09:06
Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope
Published on: March 24, 2019
Superconductividad a 43 K en el SmFeAsO1-xFx
1Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China. chenxh@ustc.edu.cn
Nature
|May 27, 2008
Resumen
Los investigadores descubrieron un nuevo superconductor a base de hierro, SmFeAsO{1-x) F{x), que exhibe superconductividad a 43 K. Este hallazgo supera los récords anteriores no relacionados con el óxido de cobre y ofrece nuevas vías para la investigación de la superconductividad a alta temperatura.
Área de la Ciencia:
- Física de la materia condensada Física de la materia condensada
- Ciencia de los materiales Ciencia de los materiales.
- Química del estado sólido.
Sus antecedentes:
- La superconductividad de alta temperatura de transición (alta T ((c)) se observa principalmente en los óxidos de cobre.
- El máximo teórico T ((c) es de alrededor de 40 K, con MgB ((2) que mantiene el récord no-óxido de cobre a 39 K.
- Los oxypnictides en capas de metales de tierras raras (LnOFeAs) están surgiendo como una nueva clase de superconductores.
Objetivo del estudio:
- Explorar nuevos materiales para la superconductividad de alta T (c) más allá de los óxidos de cobre.
- Para investigar la superconductividad en la estructura tipo ZrCuSiAs de SmFeAsO(1-x) F(x).
- Establecer una nueva plataforma de materiales para comprender los mecanismos de la superconductividad a alta temperatura.
Principales métodos:
- Síntesis y caracterización de SmFeAsO{1-x) F{x) con una estructura de tipo ZrCuSiAs.
- Mediciones de la resistividad eléctrica para determinar la temperatura de transición superconductora (T ((c)).
- Mediciones de susceptibilidad magnética para confirmar la superconductividad a granel.
Principales resultados:
- El descubrimiento de la superconductividad a granel en SmFeAsO{1-x) F{x).
- Se logró una temperatura de transición superconductora (T ((c)) tan alta como 43 K.
- Esta T(c) supera el récord anterior para superconductores sin óxido de cobre.
Conclusiones:
- SmFeAsO{1-x) F{x) representa un avance significativo en la superconductividad no-óxido de cobre.
- El nuevo material proporciona un sistema valioso para la investigación fundamental sobre los orígenes de la superconductividad de alta T (c).
- Este descubrimiento amplía el alcance de los materiales disponibles para explorar los fenómenos de superconductividad.
Videos de Conceptos Relacionados
01:24Superconductor
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a superconductor. In 1911, Heike Kamerlingh Onnes of Leiden University, a Dutch physicist, observed a relation between the temperature and the resistance of the element mercury. The mercury sample was then cooled in liquid helium to study the linear dependence of resistance on temperature. It was observed that, as the temperature decreased, the...
01:28Types Of Superconductors
A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the only interesting phenomenon as materials reach their transition temperatures. A second effect is the exclusion of magnetic fields. This is known as the Meissner effect. A light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor. High-speed trains that levitate on strong...
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...
01:18Fermi Level
The Fermi-Dirac function is represented by an S-shaped curve indicating the probability of an energy state being occupied by an electron at a given temperature. The Fermi level is the energy level at which there is a fifty percent chance of finding an electron, and it is positioned between the lower-energy valence band and the higher-energy conduction band.
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
01:17Theory of Metallic Conduction
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
01:31Magnetic Susceptibility and Permeability
In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...