SUPERCONDUCTORSPHENOMENON DISCOVERED

BY K. ONNES IN 1911. AND HE HAD WON NOBEL

PRIZE FOR THIS INVENTION IN 1913.

ACCORDING TO HIM "WHEN A MATERIAL IS COOLED BELOW A SPECIFIED TEMPERATURE IT TOTALLY LOOSES ITS PROPERTY OF RESISTANCE AND BECOME A SUPERCONDUCTOR".THIS SPECIFIED TEMPERATURE IS KNOWN AS CRITICAL TEMPERATURE AT WHICH A MATERIAL TURNS INTO A SUPERCONDUCTOR.

TEMPERATURE DEPENDENCE OF RESISTIVITY IN SUPERCONDUCTING

MATERIAL-:

EFFECT OF MAGNETIC FIELD-:

IN 1913 K. ONNES OBSERVED THAT SUPERCONDUCTIVITY IS DESTROYED IF A SUFFICIENT STRONG MAGNETIC FIELD IS APPLIED. THE MINIMUM MAGNETIC FIELD WHICH IS NECESSARY TO REGAIN ITS NORMAL STATE IS CALLED CRITICAL MAGNFIELD.

Meissner effect-:

IN 1933 MEISSNER OBSERVED THAT IF A SUPERCONDUCTOR IS COOLED BELOW CRITICAL TEMPERATURE CORRESPONDING TO THAT FIELD, THEN LINES OF INDUCTION ARE EXPELLED FROM THE MATERIAL . AND THIS EFFECT IS NAMED AS MEISSNER EFFECT.

BCS THEORY (explanation of superconductivity)-:

IN 1957 BARDEEN COOPER AND SCRIEFFER GAVE A THEORY TO EXPLAIN SUPERCONDUCTIVITY NAMED AS BCS THEORY SHOWS LATTICE DISTORTION

ELECTRON-LATTICE-ELECTRON INTERACTION VIA A PHOTON FIELD

HIGH TEMPERATURE SUPERCONDUCTORS-:

IN 1986 BEDNORZ AND ALEX MULLER DISCOVERED THE HIGH TEMPERATURE SUPERCONDUCTIVITY IN CERAMICS AND THEY WERE AWARDED THE NOBEL PRIZE IN PHYSICS IN 1987THEY MADE A PARTICULAR TYPE OF CERAMIC MATERIAL WHICH REMAINED A SUPERCONDUCTOR AT A TEMPERATURE AS HIGH AS 30 K. EXAMPLES OF HIGH TEMPERATURE SUPERCONDUCTOR ARE-:

APPLICATIONS OF SUPERCONDUCTORS

(1) POWER TRANSMISSION(2)SUPERCONDUCTING MAGNETS(3) FOR PROGRESS OF COMPUTER TECHNOLOGY(4) SUPERCONDUCTING QUANTUM INTERFERENCE DEVICES (SQUIDS)(5) VERY STRONG MAGNETIC FIELD