Name: superconductors and magnetic levitation
Uploaded: 2025-05-22T09:05:52.000Z
Duration: 1 min 28 s
Channel: JoVE

K12 Standards

Virginia  Standards of Learning

HIgh School

Physics

PH.9

PH.9.g

Types Of Superconductors

Lorsqu’un aimant permanent est placé sur n’importe quel type de matériau supraconducteur, l’aimant est repoussé et lévite dans une position stable en raison de l’effet Meissner. Les supraconducteurs sont classés en groupes de type I et de type II en fonction de leur comportement et de leurs caractéristiques.
Les supraconducteurs de type I agissent comme des conducteurs lorsqu’ils fonctionnent à température ambiante. Cependant, lorsqu’elle est refroidie en dessous de la température critique, le mouvement moléculaire à l’intérieur de la substance est réduit, ce qui permet au courant de circuler aussi librement que possible.
Ils sont généralement constitués de métaux purs comme le mercure, le zinc, l’aluminium, le plomb, etc., et obéissent entièrement à l’effet Meissner tout en ayant un faible champ magnétique critique.
Les supraconducteurs de type II présentent une phase intermédiaire de propriétés mixtes ordinaires et supraconductrices à des températures et des champs intermédiaires au-dessus des phases supraconductrices.
Ils comprennent généralement du niobium élémentaire, du vanadium, du technétium et des alliages métalliques ou des oxydes complexes.
Les supraconducteurs de type II obéissent partiellement à l’effet Meissner et ont deux champs magnétiques critiques.

<ol>
	<li>OpenStax. (2019). Physique universitaire Vol. 2. [Version Web], p. 396 à 398. Tiré de <a href="https://openstax.org/books/university-physics-volume-2/pages/9-6-superconductors">https://openstax.org/books/university-physics-volume-2/pages/9-6-superconductors</a></li>
</ol>

types de supraconducteurs

Un supraconducteur est une substance qui offre une résistance nulle au courant électrique lorsqu'il descend en dessous d'une température critique. La résistance nulle n'est pas le seul phénomène intéressant lorsque les matériaux atteignent leur température de transition. Un deuxième effet est l'exclusion des champs magnétiques. Cela est connu sous le nom d'effet Meissner. Un aimant léger et permanent placé au-dessus d'un échantillon supraconducteur lévitera dans une position stable au-dessus du supraconducteur. Des trains à grande vitesse qui lèvent sur de puissants aimants supraconducteurs ont été développés, éliminant les frottements normalement ressentis entre le train et les rails. Le 3 avril 1997, la ligne de test Yamanashi Maglev au Japon a officiellement ouvert, et en avril 2015, le véhicule de test MLX01 a atteint une vitesse de 374 mph en utilisant de puissants aimants supraconducteurs.

Les supraconducteurs peuvent être classés en deux catégories, les supraconducteurs de Type I et les supraconducteurs de Type II.

Trente métaux purs présentent une résistivité nulle en dessous de leur température critique et montrent l'effet Meissner, la propriété d'exclusion des champs magnétiques de l'intérieur du supraconducteur tant que le supraconducteur est à une température inférieure à la température critique. Ces métaux sont appelés des supraconducteurs de Type I. La supraconductivité ne se manifeste que en dessous de leurs températures critiques et en dessous d'une force magnétique critique. Les supraconducteurs de Type I ont des applications pratiques limitées car la force du champ magnétique critique nécessaire pour détruire la supraconductivité est assez faible.

Les supraconducteurs de Type II ont des champs magnétiques critiques beaucoup plus élevés et peuvent supporter des densités de courant beaucoup plus élevées tout en restant dans l'état supraconducteur. Diverses céramiques contenant du baryum-cuivre-oxyde ont des températures critiques beaucoup plus élevées pour la transition vers un état supraconducteur. Les matériaux supraconducteurs appartenant à cette sous-catégorie des supraconducteurs de Type II sont souvent classés comme des supraconducteurs à haute température.

Types De Supraconducteurs

Un supraconducteur est une substance qui offre une résistance nulle au courant électrique lorsqu’il descend en dessous d’une température critique. La résistance zéro n’est pas le ...

Education

Enseignement

JoVE Core

Physique

Unit 1

Unité 1

Electromagnetic Induction

Induction électromagnétique

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

superconductors and magnetic levitation

Superconductors are materials that can carry electric current with zero resistance when they are cooled below a critical temperature. At this point, they also show the Meissner effect, which means they push magnetic fields out of their interior. A light permanent magnet can then levitate in a stable position above the superconducting sample.

This magnetic levitation has real uses. High-speed trains have been built with strong superconducting magnets so they can float above the track and avoid friction. The Yamanashi Maglev test line in Japan opened on April 3, 1997. In April 2015, the MLX01 test vehicle reached 374 mph using strong superconducting magnets.

Superconductors are grouped into Type I and Type II superconductors. Type I superconductors are about thirty pure metals that show zero resistivity below their critical temperature and also display the Meissner effect. They work only below their critical temperature and below a critical magnetic field strength. Because that critical magnetic field is low, Type I superconductors have limited practical use.

Type II superconductors can stay superconducting in much higher magnetic fields. They can also carry much higher current densities while remaining in the superconducting state. Many ceramic superconductors that contain barium-copper-oxide fall into this group. These materials often have much higher critical temperatures, so they are often called high-temperature superconductors.

Superconductors and Magnetic Levitation

induction

Magnetic Flux and Induced Current

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dc generator

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superconductor

Superconductor Critical Temperature

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types of superconductors

Superconductors are materials that can carry electric current with zero resistance when they are cooled below a critical temperature. At this point, they also show the Meissner effect, which means they push magnetic fields out of their interior. A light permanent magnet can then levitate in a stable position above the superconducting sample. This magnetic levitation has real uses. High-speed trains have been built with strong superconducting magnets so they can float above the track and avoid...

faraday's law

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lenz's law

Magnet Motion and Induced Current

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motional emf

Induced Current from Changing Magnetic Flux

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faraday disk dynamo

Faraday Disk Dynamo and DC Output

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induced electric fields

Faraday’s Law and Induced EMF

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induced electric fields: applications

Electric Fields from Changing Magnetism

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eddy currents

Eddy Currents in Recycling, Brakes, and Heat

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Maxwell’s Fix for Changing Currents

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Maxwell’s Fix for Charging Capacitors

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electromagnetic fields

Electric and Magnetic Fields in Motion

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maxwell's equation of electromagnetism

Maxwell's Equations and Light Waves

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symmetry in maxwell's equations

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electric generator: alternator

How Alternators Produce AC Power

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key terms and concepts

Learn how superconductors show zero resistance, the Meissner effect, and magnetic levitation, then compare Type I and Type II superconductors.

Superconductors and Magnetic Levitation | JoVE K12

physics

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Superconductors and Magnetic Levitation

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