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Electromagnetic Induction

Superconductors and Magnetic Levitation

Description

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 superc...

Transcript

当一块永磁体置于任何类型的超导材料上方时,由于迈斯纳效应,磁体会受到排斥并稳定地悬浮在空中。根据其行为和特性,超导体可分为I型和II型两类。

第一类超导体在室温下工作时表现为导体。然而,当温度降低至临界温度以下时,物质内部的分子运动减弱,使得电流能够尽可能自由地流动。

它们通常由汞、锌、铝、铅等纯金属组成,完全遵循迈斯纳效应,但具有较低的临界磁场。

第二类超导体在中间温度和高于超导相的磁场下,表现出普通导电性与超导性共存的中间相态。

它们通常由元素铌、钒、锝以及金属合金或复合氧化物组成。

II型超导体部分遵循迈斯纳效应,并具有两个临界磁场。

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