2. Superconductors—
Are materials that offer no resistance to electrical
current.
Some metals when they are cooled below their
critical temperature exhibits the zero resistivity or
infinite conductivity. These metal are called
superconductor metals.
Examples of superconductors --include
aluminium, niobium, magnesium diboride,
cuprates.
Mercury-- It becomes superconductor at 4k.
Properties of Superconductors
The superconducting material shows some
extraordinary properties.
1.Zero electric resistance (infinite conductivity)
2.Meissner Effect: Expulsion of magnetic field
3.Critical Temperature/transition temperature
4.Critical Magnetic field
3.
4. Superconductivity-- is the ability of certain materials to conduct electric current
with practically zero resistance.
In superconducting state the materials expel the magnetic field.
Critical temperature/transition temperature
The temperature at which the metals change from normal conducting state to
superconducting state, is called critical temperature/transition temperature.
`Meissner effect --When Superconductors, are cooled below the critical temperature,
they expel magnetic field and do not allow the magnetic field to penetrate inside
them. This phenomenon in superconductors is called Meissner effect.
This phenomenon was discovered by German physicists “Walther Meissner” and
“Robert Ochsenfeld” in 1933.
Meissner state breaks when the magnetic field (either external or produced by current
flowing superconductor itself) increases beyond a certain value and sample starts
behaving like an ordinary conductor.
Critical Magnetic Field -- certain value of magnetic field beyond which
superconductor returns to ordinary state is called Critical Magnetic Field.
The value of the critical magnetic field depends on temperature.
5. The value of the critical magnetic field increases when the temperature below the
critical temperature reduces.
Type-I Superconductor
These types of superconductors lose their superconductivity very simply when it
is placed in the magnetic field at the critical magnetic field (Hc). After that, it will
become like a conductor.
These types of semiconductors are also named as soft superconductors due to
the reason of loss of superconductivity. These superconductors obey the
Meissner effect completely.
The superconductor examples are Zinc and Aluminum.
Type-II Superconductor
This kind of superconductor will lose their superconductivity slowly but not simply
as it is arranged within the exterior magnetic field.
This type of semiconductor is also named as hard superconductors due to the
reason they lose their superconductivity slowly but not simply. These
semiconductors will obey the effect of Meissner but not totally. The best examples
of these are NbN and Babi3.
6. Applications of Super Conductor
The applications of superconductors include the following.
•These are used in generators, particle accelerators, transportation, electric
motors, computing, medical, power transmission, etc.
•Superconductors mainly used for creating powerful electromagnets in MRI
scanners. So these are used to divide. They can also be used to separate magnetic
and non-magnetic materials
•This conductor is used to transmit power for long distances
•Used in memory or storage elements.
