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Chapter 12: Solid state physics 69 Within a superconductor the magnetic feld is 0: the Meissner effect . There are type I and type II superconductors. Because the Meissner eFFect implies that a superconductor is a perFect diamagnet holds in the superconducting state: ± H = μ 0 ± M . This holds For a type I superconductor, For a type II superconductor this only holds to a certain value H c1 , For higher values oF H the superconductor is in a vortex state to a value H c2 , which can be 100 times H c1 . IF H becomes larger than H c2 the superconductor becomes a normal conductor. This is shown in the fgures below. Type I ± ² μ 0 M H H c ³ ³ ³ ³ ³ ³ ³ ³ Type II ± ² μ 0 M H H c1 H c2 ³ ³ ³ ³ ³ · · · · · · · · · · · · · · · The transition to a superconducting state is a second order thermodynamic state transition. This means that there is a twist in the T - S diagram and a discontinuity in the C X - T diagram. 12.8.2 The Josephson effect ±or the Josephson eFFect one considers two superconductors, separated by an insulator. The electron wave-
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