SUPER CONDUCTIVITY

& ITS APPLICATION

TODAY WE ARE GOING TO DISCUSS ABOUT

Super conductivity General properties

Observations regardingApplications

Super conductor are the material having almost zero resistivity and behave as diamagnetic below the super conducting transition temperature.

Super conductors are PERFECT conductors.

ABSTRACT

GENERAL PROPERTIES OF SUPERCONDUCTORS Virtually zero electrical resistance.

Perfect diamagnetic property.

Critical field depends upon temperature of superconducting material.

Heavy current effect destroys superconductivity properties.

At very high pressure Tc is directly proportional to pressure.

Tc is inversely proportional to square root of At.wt of the isotope of single superconductor.

THEORIES OF SUPER CONDUCTIVITY

LONDON THEORY -1935

GINZBURG-LANDAU THEORY – 1950

BARDEEN, COOPER, SCHRIEFFER THEORY - 1957

BCS THEORYPrinciple:

The electron experience a special kind of attractive interaction, over coming the coulombs force of repulsion between them, as a result cooper pairs are formed.

At low temperature , these pairs move through lattice without resistance and hence behave as superconductor.

Super conductor lattice

Due to attract of electron by positive charge, ions in conductor is disturbed

Ions attracted by positive charges

Due to deformation positive charge increased

Electrons get attracted due to increased positive charges

Cooper pairs formed

ADVANTAGES Can carry large quantities of energy without

heat loss.

Able to generate strong magnetic fields.

Superconductors beneficial applications in medical imaging techniques.

New superconductive films may result in miniaturization .

Superconductors increased speed in computer chips.

DISADVANTAGE

Superconducting materials conduct current at only given temperature known as transition temperature.

Superconductors still do not show up in most everyday electronics.

JOSEPH DEVICESPrinciple:

Persistent current in D.C voltage.

Construction:A thin layer of insulators is placed between the

superconductors.Both superconductors are connected to a battery .

Working :LET US SEE THE WORKING OF JOSEPH

DEVICE IN THE SUCCEEDING SLIDES.

Josephson devices

Voltage V applied across super conductor 1

Current increases due to tunneling effect

APPLICATIONS OF SUPER CONDUCTIVITY

Super conducting generator

Super conducting transmission line cables

Superconducting magnetic energy storage system (smes)

SUPER CONDUCTING GENERATOR

Converts mechanical to electrical energy.

Own magnetic field is produced.

Current and flux density determines the output.

Field windings produces higher magnetic field.

Superconductors have extremely high current carrying capacity.

SUPER CONDUCTING TRANSMISSION LINE CABLES Provides ZERO resistance.

Due to LOW VOLTAGE, high current transmission occurs.

SMALL physical size.

Reduced CLEARANCE for terminal faculties.

Quick RECOVERY after fault.

Overload capability.

SUPERCONDUCTING MAGNETIC ENERGY STORAGE SYSTEM (SMES) Current carrying wire generates a

magnetic field.

Superconducting solenoids made by wrapping a superconducting wire in the coil from are functionally superior to conventional solenoids.

Zero DC electrical resistance.

No resistive losses.

Super conducting speaker

Super Conducting Tube Direct-Plug Solar Water Heater

Magnetically levitating trains

LET US FINISH THE PRESENTATION WITH AN INTERESTING CLIPThank you !