The interior of a bulk superconductor cannot be penetrated by a weak magnetic field, a phenomenon known as the Meissner effect. When the applied magnetic field becomes too large, superconductivity breaks down. Superconductors can be divided into two types according to how this breakdown occurs. In type-I superconductors, superconductivity is abruptly destroyed via a first order phase transition when the strength of the applied field rises above a critical value Hc. This type of superconductivity is normally exhibited by pure metals, e.g. aluminium, lead, and mercury. The only alloy known up to now which exhibits type I superconductivity is TaSi2. The covalent superconductor SiC:B, silicon carbide heavily doped with boron, is also type-I.
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| - Superconductors de tipus I (ca)
- Superconductor de tipo I (es)
- Superkonduktor tipe I (in)
- Type-I superconductor (en)
- 第一类超导体 (zh)
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| - Los superconductores de tipo I son superconductores que en presencia de un campo magnético establecen corrientes superficiales que impiden que dicho campo penetre en el material; este fenómeno se conoce como efecto Meissner. Fueron los primeros superconductores en ser descubiertos, y su comportamiento está ampliamente explicado dentro del marco de la teoría BCS, propuesta en 1957. (es)
- Superkonduktor tipe I adalah salah satu menurut responnya terhadap medan magnet; superkonduktor tipe I memiliki satu ambang : jika medan lebih kuat dari ambang ini, sifat superkonduktornya akan hilang dan jika lebih lemah, medan magnet akan ditolak seluruhnya. Superkondukter tipe I dibedakan dari yang memiliki dua ambang batas, jika besar medan magnet di antara dua batas ini, medan tersebut akan berpenetrasi sebagian secara bertahap. (in)
- The interior of a bulk superconductor cannot be penetrated by a weak magnetic field, a phenomenon known as the Meissner effect. When the applied magnetic field becomes too large, superconductivity breaks down. Superconductors can be divided into two types according to how this breakdown occurs. In type-I superconductors, superconductivity is abruptly destroyed via a first order phase transition when the strength of the applied field rises above a critical value Hc. This type of superconductivity is normally exhibited by pure metals, e.g. aluminium, lead, and mercury. The only alloy known up to now which exhibits type I superconductivity is TaSi2. The covalent superconductor SiC:B, silicon carbide heavily doped with boron, is also type-I. (en)
- 由于迈斯纳效应的存在,磁场无法轻易穿过超导体。但当外加磁场达到一定强度时,磁场可以破坏超导态。就超导态被破坏的方式而言,超导体可以分为两类。第一类超导体中,一旦外加磁场突破临界磁场Hc,将发生,超导态突然消失。这样的超导态往往存在于纯金属超导体,例如铝、铅和汞中。目前已知唯一的合金材料的第一类超导体是 TaSi2。由于退磁因子的存在,材料可能会进入一种宏观上由普通态区域和超导态区域混合的中间状态。简单的说,由于物体形状对于外加磁场的影响,某些区域的磁场可能强于另一些区域的磁场,从而使得材料部分区域脱离超导态。这一现象最早由朗道描述。 临界磁场Hc也受温度T影响,Hc随着温度升高而逐渐减小,当温度升到临界温度Tc时,临界磁场Hc变为0。Hc(T)有以下关系: 当第一类超导体处于超导态时,其内部磁场为零(迈斯纳效应),根据电动力学原理: 其中B是磁感应强度,M是磁矩,H是磁场强度。当外界磁场低于临界临界磁场Hc时,磁矩M随外加磁场线性变化。 物理上由伦敦穿透深度λ和ξ的比值(金兹堡-朗道参数)的大小决定一个超导体属于第一类还是第二类。第一类超导体满足 0 < < 1/√2, 而第二类超导体满足 > 1/√2 。 (zh)
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| - Los superconductores de tipo I son superconductores que en presencia de un campo magnético establecen corrientes superficiales que impiden que dicho campo penetre en el material; este fenómeno se conoce como efecto Meissner. Fueron los primeros superconductores en ser descubiertos, y su comportamiento está ampliamente explicado dentro del marco de la teoría BCS, propuesta en 1957. (es)
- Superkonduktor tipe I adalah salah satu menurut responnya terhadap medan magnet; superkonduktor tipe I memiliki satu ambang : jika medan lebih kuat dari ambang ini, sifat superkonduktornya akan hilang dan jika lebih lemah, medan magnet akan ditolak seluruhnya. Superkondukter tipe I dibedakan dari yang memiliki dua ambang batas, jika besar medan magnet di antara dua batas ini, medan tersebut akan berpenetrasi sebagian secara bertahap. (in)
- The interior of a bulk superconductor cannot be penetrated by a weak magnetic field, a phenomenon known as the Meissner effect. When the applied magnetic field becomes too large, superconductivity breaks down. Superconductors can be divided into two types according to how this breakdown occurs. In type-I superconductors, superconductivity is abruptly destroyed via a first order phase transition when the strength of the applied field rises above a critical value Hc. This type of superconductivity is normally exhibited by pure metals, e.g. aluminium, lead, and mercury. The only alloy known up to now which exhibits type I superconductivity is TaSi2. The covalent superconductor SiC:B, silicon carbide heavily doped with boron, is also type-I. Depending on the demagnetization factor, one may obtain an intermediate state. This state, first described by Lev Landau, is a phase separation into macroscopic non-superconducting and superconducting domains forming a Husimi Q representation. This behavior is different from type-II superconductors which exhibit two critical magnetic fields. The first, lower critical field occurs when magnetic flux vortices penetrate the material but the material remains superconducting outside of these microscopic vortices. When the vortex density becomes too large, the entire material becomes non-superconducting; this corresponds to the second, higher critical field. The ratio of the London penetration depth λ to the superconducting coherence length ξ determines whether a superconductor is type-I or type-II. Type-I superconductors are those with 0 < λ/ξ < 1/√2, and type-II superconductors are those with λ/ξ > 1/√2. (en)
- 由于迈斯纳效应的存在,磁场无法轻易穿过超导体。但当外加磁场达到一定强度时,磁场可以破坏超导态。就超导态被破坏的方式而言,超导体可以分为两类。第一类超导体中,一旦外加磁场突破临界磁场Hc,将发生,超导态突然消失。这样的超导态往往存在于纯金属超导体,例如铝、铅和汞中。目前已知唯一的合金材料的第一类超导体是 TaSi2。由于退磁因子的存在,材料可能会进入一种宏观上由普通态区域和超导态区域混合的中间状态。简单的说,由于物体形状对于外加磁场的影响,某些区域的磁场可能强于另一些区域的磁场,从而使得材料部分区域脱离超导态。这一现象最早由朗道描述。 临界磁场Hc也受温度T影响,Hc随着温度升高而逐渐减小,当温度升到临界温度Tc时,临界磁场Hc变为0。Hc(T)有以下关系: 当第一类超导体处于超导态时,其内部磁场为零(迈斯纳效应),根据电动力学原理: 其中B是磁感应强度,M是磁矩,H是磁场强度。当外界磁场低于临界临界磁场Hc时,磁矩M随外加磁场线性变化。 第一类超导体的临界磁场Hc通常比较小,很难用于实际应用,因此第一类超导体也通常被称为软超导体。而第二类超导体往往具有两个临界磁场。第一个、较低的临界磁场Hc1描述磁通漩涡穿过材料,但材料在这些磁通漩涡之外仍然保持超导态的相变过程。当这些磁通漩涡的密度大到一定程度时,整个材料脱离超导态,这个过程对应于第二个临界磁场Hc2。Hc2往往比较大,由铌,铝,锗合成的合金可以达到大于40 特斯拉的Hc2。第二类超导体也被称为硬超导体,因其具有很高的上限临界磁场,被广泛应用于高磁场超导线圈领域。 物理上由伦敦穿透深度λ和ξ的比值(金兹堡-朗道参数)的大小决定一个超导体属于第一类还是第二类。第一类超导体满足 0 < < 1/√2, 而第二类超导体满足 > 1/√2 。 (zh)
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