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SUPERCONDUCTIVITY
INTRODUCTION
In 1848 Lord Kelvin suggested that the lowest limit of temperature is absolute zero (-273°C or 0
kelvin)
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For this he
was awarded the nobel prize in 1913
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Under normal
condition it is ex[ected that the temperature decreases kinetic energy decreases and so does
resistance
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1 kelvin
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This newly discovered phenomenon
was called as superconductivity and materials possessing this property of offering no resistance or
zero resistance to the passage of electricity are superconductors
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Thus superconductors are also used to produce magnetic
fields of high strength
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It does so by creating
small currents along its surface which cancel out all the magnetic fields that come in contact with the
material
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They found that
when these materials were cooled to the point that was useful for conducting the magnetic field
intensity dropped to almost zero
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These
currents can then cancel out the magnetic field which makes flow in the same direction
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CLASSIFICATION OF SUPERCONDUCTORS
1) Based on the microstructural properties of superconducting material and its magnetic
behaviour superconductors are classified as IDEAL SUPERCONDUCTORS and HARD
SUPERCONDUCTORS
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Thus Meissner effect differs from ideal and hard superconductor
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Usually Neobium alloys are
used as conventional superconductors
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3 K
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Hence
they have been replaced by Vanadium Gallium alloy which can be easily manufactured in the
form of wires
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B) HARD SUPERCONDUCTORS:
The materials that behave as superconductors at unusually high temperature
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2) In nuclear fusion research to produce powerful magnetic fields
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4) In SQUIRDS (Superconducting Quantum Interferance Devices) Used in electronics to
produce very low noise amplifiers
5) They are used in power transmission in computers to get rid of unwanted heat and in
powerful electromagnets

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