The document discusses superconductors, which are materials that lose all electrical resistance below a critical temperature. It describes how superconductivity was discovered in 1911 by Kammerlingh Onnes. The key properties of superconductors are zero resistance, the Meissner effect of expelling magnetic fields, and ability to levitate objects. There are two types of superconductors based on their critical magnetic field properties. Applications include MRI, maglev trains, and particle accelerators. Advantages are efficient power transmission and small devices, while limitations are the need for extremely low temperatures and brittleness.

1. SUPER-CONDUCTOR
Muhammad Hamza
5th Semester
B.Sc. Textile Technology

2. CONTENTS
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Superconductors
Discovery
Properties
Types
Application of
superconductorsAdvantages and
Disadvantages
Limitations

3. SUPERCONDUCTOR
 A Superconductor is a material that loses all its resistance to the flow of
electric current when it is cooled below a certain temperature called the
critical temperature or transition temperature Tc.
 Examples : Mercury(Hg), Vanadium(V),
Yttrium barium copper oxide(YBCO)
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4. TRANSITION TEMPERATURE
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5. HISTORY
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• Superconductivity was first
discovered in 1911 by the
Dutch physicist,Heike
Kammerlingh Onnes.

6. HISTORY
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• Onnes felt that a wire’s resistance would vanish if it is
cooled too much. This suggested that there would be a
steady decrease in electrical resistance, allowing for
better conduction of electricity.
• Onnes passed a current through a pure mercury wire
and measured its resistance as he gradually decreased its
temperature. To his surprise there was little or no
resistance at 4.2 K.

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8. PROPERTIES
• Electrical resistance: Virtually zero electrical resistance.
• Effect of impurities: When impurities are added to superconducting
elements, the superconductivity is not loss but the T c is lowered.
• Effects of pressures and stress: certain materials exhibits
superconductivity on increasing the pressure in superconductors, the
increase in stress results in increase of the T c value
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9. CONTI…..
• Magnetic field effect: If Strong magnetic field applied to a
superconductors below its T C , the superconductors undergoes
a transition from superconducting state to normal state.
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10. MEISSNER EFFECT
• The complete expulsion of all magnetic field by a superconducting material is called
“Meissner effect”
• Magnetic field does not penetrate the sample
• Normal state: T > Tc
• Superconducting state : T < Tc
• The Meissner effect is a distinct characteristics of a superconducting from a normal
perfect conductor. In addition, this effect is exhibited by the superconducting materials
only when the applied field is less then the critical field Hc.
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12. MAGNETIC LEVITATION (MAGLEV)
• Magnetic Levitation or Maglev is the process by which an object is
suspended above another object with no other support but magnetic fields.
• The phenomenon of magnetic levitation is based on Meissner effect.
• The magnetic levitation is brought about by enormous repulsion between
two highly powerful magnetic fields.
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13. MAGNETIC
LEVITATION
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14. TYPES 1 SUPERCONDUCTORS
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These superconductors are
called as soft
superconductors.
2. Only one critical magnetic
field exist for these
superconductors.
3. The critical field value is
very low.
4. These superconductors
exhibit perfect and
complete Meissner effect.
5. These materials have
limited technical
applications because of very
low field strength value.
Examples : Pb, Hg, Zn, etc.

15. TYPE 2 SUPERCONDUCTORS
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These
superconductors
are called as
hard
superconductors.
2. Two critical
fields exist for
these
superconductors.
3. The critical
field value is very
high.
4. These
superconductors do
not exhibit perfect
and complete
Meissner effect.
5. These materials
have wider
technological
applications because
of very high field
strength value.
Examples : Nb3Ge,
Nb3Si, etc.

16. APPLICATIONS
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Maglev train
Magnetic
Resonance
Imaging (MRI)
Superconducting
wire
Rail gun and coil
gun magnets.
Electric motors
and generators
SQUID:
Superconducting
Quantum Interference
Device, it is used in
Particle accelerators
and many other
devices.

17. APPLICATIONS
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18. ADVANTAGES
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Magnetic
levitation
Power & cost
efficient
Reduces the size &
weight of motors,
generators &
supporting
equipments

19. DISADVANTAGES
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Extremely brittle Very low critical temperature Not applicable for consumer
electronics

20. LIMITATIONS
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• The biggest problem of the superconductors is their
‘’COOL’’ nature . Creating a temperature near 0 k is not
a easy job. Cooling arrangements involve a huge cost
which is why superconductors have yet to make a really
big impact on the world, despite being discovered a
century ago.

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