This document summarizes an active learning assignment on the topic of superconductors. It discusses three main types of superconductors: Type 1, which exhibit the Meissner effect and have low critical magnetic fields; Type 2, which behave differently in increasing magnetic fields and are used for most engineering applications; and classifications based on the coolant (low-temperature using liquid helium, and high-temperature above liquid nitrogen). Applications discussed include magnetic levitation, Josephson junction devices like SQUIDs, power transmission, MRI machines, magnetic field generation, and cryotrons for fast and efficient computing.

1. Active Learning Assignment
Subject :Physics (2110011)
Branch :Mechanical Engg.
Division :KG-1
Presented By: Patel Parth .V (150120119132)
Patel Parth .R (150120119133)
Patel Jaydev (150120119127)
Topic:- Types and Applications of Superconductors
Guided by :- Prof. Umang Patel
1

2. A Superconductor is a material that losses all its
resistance (offer zero resistance) to the flow of
electric current when it is cooled below a certain
temperature called critical temperature or
transition temperature (Tc)
Examples- Mercury(Hg), Zinc(Zn), Vanadium(V),
Tin(Sn) and Niobium(Nb).

4. Based on behavior of superconductor in an
applied magnetic field.
 Type 1 superconductor:-
 Type 1 superconductor exhibits complete Meissner effect.
 They are completely diamagnetic. And the values of (Hc)
[Critical magnetic field] is very low.
 They are also called soft-superconductor because of their
tendency to allow magnetic field penetration even though for
lower applied field.
 Examples- alloys and some compound superconductor exhibits
type 1 behavior.

5. Type 2 Superconductor :-
 Type 2 superconductor behaves differently in an increasing
field.
 They are mostly used in all engineering applications.
 They are also called hard superconductor because of relatively
large magnetic field requirement to bring them back to their
normal state.
Type 1 Type 2
Material ( Hc) in
tesla
Material (Hc) in
tesla
Ta
0.083
(Y1Ba2Cu3O7) 300
Pb
0.08
(Ba2-XBXCuO4) 150
Hg (Nb3Sn) 24.5

7. Based on coolant used achieve superconductivity
phenomena in material
Low-Temperature Superconductor:-
 Superconductor that requires liquid helium as coolant are called
low-temperature superconductor.
 Liquid helium temperature is 4.3k above absolute zero
temperature.
High-Temperature Superconductor:-
 Superconductors having their critical temperature above liquid
nitrogen(77k or -196c) are called high-temperature
superconductors.
 The highest transition temperature currently known is 138k, in a
thallium-doped mercuric cuprate comprises the element like Hg,
Tl, Ba, Ca, Cu and oxygen.

8. Sr. No Material (Tc)in k
1 (Pb2YSr2Cu3O8) 77
2 Y-Ba-Cu-O (Y1Ba2Cu3O7) 93-95
3 Tl(Bi)-Ba(Sr)-Ca-Cu-O 122-125
4 Hg-Ba-Ca-Cu-O 130-135

9. The high temperature superconductor have limited practical
application because they ceramics which are brittle.
 But in thin film technology these materials can find their
applications in the electronic field as high-speed computers.

10. 1)Magnetic Levitation(Maglev)
 Magnetic levitation or maglev is the process by which
an object is suspended above another object.
 We know that a perfect diamagnetic substance
repels a magnetic field.
 Hence diamagnetic properties of superconductor
make them suitable for achieving frictionless motion
in motors and bearing.
 The levitation is achieved by two ways:
1) Electromagnetic Suspension
2) Electrodynamic Suspension

11. 2) Josephson Effect and it’s application
 Josephson junction is formed by a layer of thin strip of
insulator between two superconductor.
 The wave nature of moving particles make the electron
to tunnel through the barrier(insulator), the electron
can tunnel from one superconductor to other.
 As a consequence of the tunneling of electron across
the insulator, there is a net current across the junction.
This is called Josephson effect.
 It is used in sensitive magnetometers called
SQUID(Superconducting Quantum Interference
Device)

12.  A SQUID is formed by connecting two Josephson
junction in parallel.
 It is used to detect small magnetic flux.
 This device can detect voltage as small as (10-15)V.
 Also Magnetic changes as small as (10-21) T can be
detected.
 Weak magnetic field produced by biological current
such as those in the brain can also be detected using
SQUIDs.
 SQUIDs detector are used to detect the level of iron in
liver- so that iron built-up can be treated before harm is
done to the body.

13. 3) Some Other application of Superconductors:
 They are used to transmit electrical power to long distance.
 Superconducting generator has the benefit of small size and low
energy consumption than the conventional generators.
 Superconducting coils are used in N.M.R (nuclear magnetic
resonance) imaging equipments which are used in hospital in
scanning the whole body to diagnose medical problem.
 Very strong Magnetic fields can be generated with coils made
of superconductor.
 Superconductor can also act as relay or switching system in
computer. They can also be used as a memory or storage
element in computer.
 Very fast and accurate computer can be constructed using
superconductors and the power consumption is also very low.

14.  Ore separation can be done efficiently using superconducting
magnet.
Example of relay or switch:
Cryotron: It is a relay or switch made of superconductors whose
size can be made very small.
 In addition, these switches consume very less current.
 The cryotron consist of two superconducting material . And the
critical field of one coil is less than the critical filed of other coil.
 If current in one coil can be controlled by the current in other
coil.