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Title 0:30

Title 0:30. Superconductivity. February 2005. Ady Stern, Baruch Rosenstein, Eli Zeldov. Superconductivity. Theoretical predictions of resistivity of metals at low T. Kamerlingh Onnes, 1911. Superconductivity. perfect conductivity. Kamerlingh Onnes, 1911. R(T) at low temperatures.

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Title 0:30

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  1. Title 0:30 Superconductivity February 2005 Ady Stern, Baruch Rosenstein, Eli Zeldov

  2. Superconductivity Theoretical predictions of resistivity of metals at low T Kamerlingh Onnes, 1911

  3. Superconductivity perfect conductivity Kamerlingh Onnes, 1911

  4. R(T) at low temperatures Experiment Theoretical predictions 1) perfect conductivity

  5. Tc M - M Isotope effect

  6. Tc M - M Isotope effect 2) Lattice is important

  7. superconductor B = 0 zero flux Meissner effect Meissner effect Perfect diamagnetism Meissner and Ochsenfeld, 1933 perfect conductor =0 =>E =0 => dB/dt = 0 constant flux 3) Perfect diamagnetism

  8. paramagnetic B > H diamagnetic B < H Magnetization of superconductors normal metal B = H B = H B H

  9. Magnetization of superconductors superconductor (type I) B = H B B=0 H Hc B=0 Meissner B=H normal

  10. 4M Magnetization of superconductors superconductor (type I) B = H B B=0 H Hc B=0 Meissner B=H normal 4M = B - H 4M Hc H Meissner normal 4M = -H M = 0

  11. 4M Magnetization of superconductors Type I Hc H 4M Meissner B=0 normal B=H

  12. Type II Hc1 Hc2 H 4M Meissner B=0 mixed B<H normal B=H Magnetization of superconductors Type I Hc H 4M Meissner B=0 normal B=H 4) Magnetic field suppresses superconductivity

  13. Magnetization of superconductors Type I Type II Hc Hc1 Hc2 H H 4M 4M Meissner B=0 normal B=H Meissner B=0 mixed B<H normal B=H Magnetization loop in Bi2Sr2CaCu2O8

  14. Type II Hc2(T) Normal mixed state H metal Hc1(T) Meissner state Tc T Phase diagram Type I H Normal Hc(T) Hc metal Meissner state Tc T

  15. thin insulator normal SC Tunneling experiments Nobel 1973 Al Al-Al2O3-Pb Al-Al2O3

  16. D thin insulator normal SC dI/dV V Tunneling experiments I Al Pb Pb normal Pb superconducting V 5) Energy gap in density of states

  17. Superconducting energy gap 2D 3.5kTc (meV) 6) Tc and energy gap are related

  18. H + H I V - R F0=h/2e=2.07x10-7 Gcm2 Little-Parks experiment time

  19. H + I V - 7) Quantization in units of h/2e F0=h/e Au h/2e

  20. Critical temperature of superconductors Tc < 30 K conventional superconductors

  21. Critical temperature of superconductors High-temperature superconductors (HTS) Tc > 140 K 8) Superconductivity mechanism in HTS is different from LTS

  22. High-temperature superconductors Nobel Prize in Physics 1987 Bi2Sr2CaCu2O8 J. Georg Bednorz K. Alexander Müller (La1.85Ba.15)CuO4 YBa2Cu3O7 Bi2Sr2CaCu2O8 Bi2Sr2Ca2Cu3O10 CuO2 double layer Tl2Ba2Ca2Cu3O10 Hg0.8Tl0.2Ba2Ca2Cu3O8.33

  23. Superconductivity phenomena • Perfect conductivity    • Perfect diamagnetism B = 0 • Magnetic field suppresses superconductivity Hc(T), Hc1(T), Hc2(T) • Magnetic flux is quantized in units of h/2e • Dynamics of the lattice is important Tc M- • Energy gap 2 • Tc and energy gap are related • Superconductivity mechanism in HTS is different from LTS

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