iii.magnétisme et...
TRANSCRIPT
![Page 1: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/1.jpg)
III.magnétisme et supraconductivité
AlNiCo permanent magnet
![Page 2: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/2.jpg)
Magnetic recording devices
Hard disk
Magnetic stripe on credit card
![Page 3: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/3.jpg)
The periodic table
![Page 4: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/4.jpg)
Magnetic moments of isolated atoms
![Page 5: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/5.jpg)
Transition metal atoms
![Page 6: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/6.jpg)
Hund's rules (Hercules lectures/VSimonet)
![Page 7: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/7.jpg)
Hund's rules (2)
![Page 8: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/8.jpg)
Domains in a ferromagnet
![Page 9: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/9.jpg)
Hysteresis loop
![Page 10: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/10.jpg)
![Page 11: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/11.jpg)
![Page 12: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/12.jpg)
![Page 13: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/13.jpg)
superconductivity
![Page 14: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/14.jpg)
superconducting compounds and their Tc
![Page 15: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/15.jpg)
Superconducting elements
![Page 16: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/16.jpg)
permanent current loops
![Page 17: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/17.jpg)
Meissner effect for a sphere
![Page 18: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/18.jpg)
Type I and type II
The mixed state (magnetic flux forming a vortex lattice)
The critical temperature versusMagnetic field in Type I and in Type II superconductors
![Page 19: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/19.jpg)
BCS theory
The building block for the BCS stateis a boson, the Cooper pair :a pair of electrons of opposite spinthat form a bound state due totheir interactionvia phonons
Superconductivityarises due to theelectron-phononInteraction !
![Page 20: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/20.jpg)
The waltz of the Cooper pairs
The BCS wavefunction
![Page 21: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/21.jpg)
The ground state is stable because there is an energy gap
Cooper pairs can be broken up byincreasing the temperatureorincreasing the magnetic fieldorincreasing the electrical current
Figure showingthe gap : the region (red)of forbidden energy
![Page 22: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/22.jpg)
The BCS equations for the gap and for Tc
The critical temperatureand the zero temperature gapdepend 1) on the Debye energy ED2) on the density of states at theFermi level N(0)3) on the effectiveelectron-electron attraction V
![Page 23: III.magnétisme et supraconductivitéhebergement.u-psud.fr/l3papp/wp-content/uploads/2015/04/diaposCh3... · BCS theory The building block for the BCS state is a boson, the Cooper](https://reader034.vdocuments.mx/reader034/viewer/2022051721/5a7b55ca7f8b9a72118bd020/html5/thumbnails/23.jpg)
Web site for nonspecialists
http://www.supraconductivite.fr/fr/index.php#supra-intro