Category Archives: Superconductivity

Silsbee rule and other properties in superconductors

Silsbee rule: An important result of the existence of critical magnetic field is that there is also critical strength of current Ic flowing in the superconductor. Exceeding this limit also causes the disturbance of superconductivity. To derive the relation between … Continue reading

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Applications of superconductors

Superconductors are useful in a number of following applications: 1. Generation and transmission of electric power. 2. Medical diagnosis 3. Electromagnets (superconducting magnets): – The type 2 superconducting wires are wound in the form of solenoids to generate strong magnetic … Continue reading

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London equations: explanation of flux penetration

As we have already derived the London equations in last article. Now let us explain the flux penetration (Meissner effect) from London equations: To explain Meissner effect from London equations consider the differential form of Ampere’s circuital law: del x … Continue reading

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London equations in superconductors: derivation and discussion

London Equations: As discussed in the Meissner effect that one of the conditions of the superconducting state is that Magnetic flux density (B) = 0 inside the superconductors that is the magnetic flux cannot penetrate inside the superconductor. But experimentally … Continue reading

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Type I and Type II superconductors

Depending upon their behavior in an external magnetic field, superconductors are divided into two types: a) Type I superconductors and b) Type II superconductors Let us discuss them one by one: 1) Type I superconductors: a). Type I superconductors are … Continue reading

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Superconductors, critical temperature, critical magnetic field and Meissner effect

Superconductors: Superconductors are the materials whose conductivity tends to infinite as resistivity tends to zero at critical temperature (transition temperature). Critical temperature (Tc): The temperature at which a conductor becomes a superconductor is known as critical temperature. Critical Magnetic Field … Continue reading

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BCS Theory of Superconductivity

A qualitative discussion of a successful theory of superconductivity was given by Bardeen, Copper and Schrieffer, known as BCS theory after the initials of their names. This theory accounts for all properties of superconductors. (a)    Electron –phonon Interaction.

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