APPLICATION OF SUPER CONDUCTING MATERIALS

                Super conductivity is of the most exciting phenomena in physics. It was discovered by Dutch Physicist H.K.Onnes in the year 1905.       
       
            Before the discovery of super conductivity, it was thought that the electrical resistivity of a material becomes zero only at absolute zero temperature.
            It was found that in some materials, the electrical resistance suddenly falls to zero when they are sufficiently cooled below a certain low temperature, known as critical temperature Tc.
  
     
            
      SQUID            SQUID stands for Super conducting Quantum Interference device.

               
PRINCIPLE

       It is based on the flux quantization in a superconducting ring. A small change in magnetic field produces variation in the quantum flux.
DESCRIPTION AND WORKING
     It is a double junction quantum interferometer. Two Josephson junctions mounted on a superconducting ring form this interferometer.

          The super conducting ring can have magnetic fields of quantum values (1,2,3,...) of flux.

          When the magnetic field is applied perpendicular to the plane of ring, the current is induced at the two Josephson junctions. The induced current produces the interference pattern and it flows around the ring. The total magnetic flux passing through the ring is quantized.

         SQUID is used to detect the variation of very minute magnetic signals in terms of quantum flux.   

APPLICATIONS
                                
                           

        SQUID is used as storage device for magnetic flux.
                                             
        It is useful in the study of earthquakes, removing paramagnetic impurities, detection of magnetic signals from the brain, heart,etc.,
                                                       
                                              

CRYOTRON
                                   
     Cryotron is a magnetically operated current switch.
PRINCIPLE
      The super conducting property of material disappears when the applied magnetic field is greater than the critical magnetic field. 
APPLICATIONS
     Oil and Gas - Surface and downhole tooling.
     Aerospace - Tooling and advanced materials
     Aircraft - Castings and components, engines and supports.

SUPER CONDUCTING MAGNETS
                                  
        The main application of super conductors at present time is the production of high magnetic field magnets.
                                     
                                           
       When the core of an electromagnet is wound with a coil of super conducting material, a large current can be maintained in the coil without heating (Joule effect).
Thus, very intense magnetic field can be constructed.                                                                                                                         

ELECTRICAL MACHINES


                                           
          Super conducting materials are used to manufacture small size electrical generators and transformers having high efficiency.
                                             
                                             

ELECTRICAL MEASURING INSTRUMENTS
                                      
                              
        Since very small voltages can cause large constant current in the super conducting materials, they are used in the construction of very sensitive electrical measuring instruments such as galvanometers.
                                  

COMPUTER MEMORY DEVICES 

        Since the super conductors can maintain the current without any loss for very long duration, they are used for memory storage in computers.
                                       



      Also, Superconductors are used to design modulators, rectifiers, commutators, cryotrons, and gating instruments. 

                   



TO KNOW MORE 
                       
                   go to -  www.superconductors.org