A presentation on superconductors and can be helpful in getting information about superconductivity its applications and types. .

1. PPRESENTED BYRESENTED BY :: VIVEK KUSHWAHAVIVEK KUSHWAHA
ECE 3ECE 3THTH
YEARYEAR
ROLL NO: 59ROLL NO: 59
PresentationPresentation
onon
Super ConductorsSuper Conductors

2. CONTENTSCONTENTS
 DefinitionDefinition
 Discovery of SuperconductivityDiscovery of Superconductivity
 Science of SuperconductivityScience of Superconductivity
 Cooper PairCooper Pair
 Meissner EffectMeissner Effect
 Types of superconductersTypes of superconducters
 Critical Temperature of someCritical Temperature of some
SuperconductorsSuperconductors
 Josephson EffectJosephson Effect
 ApplicationsApplications

3. Definition?????Definition?????
 For some materials, the resistivity vanishes atFor some materials, the resistivity vanishes at
some low temperature; they becomesome low temperature; they become
Superconductive. Superconductors have theSuperconductive. Superconductors have the
ability to conduct electrical current withability to conduct electrical current with nono
resistanceresistance(!!!), thus no loss of energy.(!!!), thus no loss of energy.

4. Discovery of SuperconductivityDiscovery of Superconductivity
 Superconductivity was first discovered in 1911 bySuperconductivity was first discovered in 1911 by
thethe Dutch physicist,Heike Kammerlingh OnnesDutch physicist,Heike Kammerlingh Onnes..
 Onnes passed a current through a very pureOnnes passed a current through a very pure
mercury wire and measured its resistance as hemercury wire and measured its resistance as he
steadily lowered the temperature. Much to hissteadily lowered the temperature. Much to his
surprise there was no resistance at 4.2K.surprise there was no resistance at 4.2K.

5. The DiscoveryThe Discovery
 At 4.2K, the Electrical Resistance Vanished.At 4.2K, the Electrical Resistance Vanished.
 Meaning Extremely Good Conduction ofMeaning Extremely Good Conduction of
Electricity-SuperconductivityElectricity-Superconductivity

6. Science of SuperconductivityScience of Superconductivity
 The behavior of electrons inside a superconductorThe behavior of electrons inside a superconductor
is vastly different.is vastly different.
 The impurities and lattice framework are stillThe impurities and lattice framework are still
there, but the movement of the superconductingthere, but the movement of the superconducting
electrons through the obstacle course is quiteelectrons through the obstacle course is quite
different.different.
 Because they bump into nothing and create noBecause they bump into nothing and create no
friction they can transmit electricity with nofriction they can transmit electricity with no
appreciable loss in the current and no loss ofappreciable loss in the current and no loss of
energy.energy.

7. The Science…The Science…
 A metal can be imagined as a lattice of positiveA metal can be imagined as a lattice of positive
ions. Electrons moving through the latticeions. Electrons moving through the lattice
constitute an electric current.constitute an electric current.
 Normally, the electrons repel each other and areNormally, the electrons repel each other and are
scattered by the lattice, creating resistance.scattered by the lattice, creating resistance.
 In superconductors, the flow of electrons is alsoIn superconductors, the flow of electrons is also
different.different.
 It was first explained by BCS theory.It was first explained by BCS theory.
 The BCS theory realized that atomic latticeThe BCS theory realized that atomic lattice
vibrations forced the electrons to pair up intovibrations forced the electrons to pair up into
teamsteams ((COOPER PAIRSCOOPER PAIRS)) that could pass all ofthat could pass all of
the obstacles which caused resistance in thethe obstacles which caused resistance in the
conductor.conductor.

8. Cooper Pair :Cooper Pair :
 Two electrons that appear to "team up" inTwo electrons that appear to "team up" in
accordance with theory - BCS or other - despiteaccordance with theory - BCS or other - despite
the fact that they both have a negative chargethe fact that they both have a negative charge
and normally repel each other.and normally repel each other.
 Below the superconducting transitionBelow the superconducting transition
temperature, paired electrons form a condensatetemperature, paired electrons form a condensate
and start to flow without resistance. This pairingand start to flow without resistance. This pairing
is caused by an attractive force betweenis caused by an attractive force between
electrons from the exchange of phonons.electrons from the exchange of phonons.

9. Animation of Cooper pairsAnimation of Cooper pairs

10. The Science….The Science….
 The superconducting state is defined by threeThe superconducting state is defined by three
very important factors: critical temperature (T),very important factors: critical temperature (T),
critical field (critical field (H)H), and critical current density (J)., and critical current density (J).
Each of these parameters is very dependant onEach of these parameters is very dependant on
the other two properties presentthe other two properties present
• critical temperature (T)critical temperature (T) The highestThe highest
temperature at which superconductivity occurs in atemperature at which superconductivity occurs in a
material. Below this transition temperaturematerial. Below this transition temperature TT thethe
resistivity of the material is equal to zero.resistivity of the material is equal to zero.
• critical magnetic field (H)critical magnetic field (H) Above this value ofAbove this value of
an externally applied magnetic field a superconductoran externally applied magnetic field a superconductor
becomes nonsuperconducting.becomes nonsuperconducting.
• critical current density (J)critical current density (J) The maximum valueThe maximum value
of electrical current per unit of cross-sectional area thatof electrical current per unit of cross-sectional area that
a superconductor can carry without resistance.a superconductor can carry without resistance.

11. Meissner EffectMeissner Effect
T > Tc
Superconductors have negative susceptibility.Superconductors have negative susceptibility.
If a superconductor is cooled below its criticalIf a superconductor is cooled below its critical
temperature while in a magnetic field, thetemperature while in a magnetic field, the
magnetic field surrounds but does not penetratemagnetic field surrounds but does not penetrate
the superconductor. The magnet induces current inthe superconductor. The magnet induces current in
the superconductor which creates a counter-the superconductor which creates a counter-
magnetic force that causes the two materials tomagnetic force that causes the two materials to
repel.repel.
T < Tc

12. Levitation of a magnet above aLevitation of a magnet above a
cooled superconductorcooled superconductor

13. Types of Superconductors:Types of Superconductors:
Superconductors can be divided into two classesSuperconductors can be divided into two classes
1.1. Type I Superconductors:Type I Superconductors: superconductivity is abruptlysuperconductivity is abruptly
destroyed when the strength of the applied field rises abovedestroyed when the strength of the applied field rises above
a critical value H. Most pure elemental superconductors,a critical value H. Most pure elemental superconductors,
except niobium, technetium, vanadium and carbonexcept niobium, technetium, vanadium and carbon
nanotubes, are Type I.nanotubes, are Type I.
2.2. Type II Superconductors:Type II Superconductors: In Type II superconductors,In Type II superconductors,
raising the applied field past a critical value Hc1 leads to araising the applied field past a critical value Hc1 leads to a
mixed state (also known as the vortex state) in which anmixed state (also known as the vortex state) in which an
increasing amount of magnetic flux penetrates the material,increasing amount of magnetic flux penetrates the material,
but there remains no resistance to the flow of electric currentbut there remains no resistance to the flow of electric current
as long as the current is not too large. At a second criticalas long as the current is not too large. At a second critical
field strength Hc2, superconductivity is destroyed. almost allfield strength Hc2, superconductivity is destroyed. almost all
impure and compound superconductors are Type II.impure and compound superconductors are Type II.

14. Critical Temperature of someCritical Temperature of some
SuperconductorsSuperconductors
MaterialMaterial Critical Temp. (K)Critical Temp. (K)
YY 0.010.01
AlAl 1.201.20
HgHg 4.154.15
PbPb 7.207.20
Nb3SnNb3Sn 18.0018.00
LaBaCuOLaBaCuO 40.0040.00
YBCuOYBCuO 92.0092.00
BiSr2Ca2Cu3Ox 113.00113.00
HgBaCaCuO 134.00134.00

15. Josephson EffectJosephson Effect
The Josephson effect is the phenomenon ofThe Josephson effect is the phenomenon of
supercurrent to flow across the insulators(!!).supercurrent to flow across the insulators(!!).
If an insulator is sandwitched between oneIf an insulator is sandwitched between one
superconductor & one normal conductor (or twosuperconductor & one normal conductor (or two
superconductors), at some voltage,current flowssuperconductors), at some voltage,current flows
due todue to tunneling of cooper pair.tunneling of cooper pair.

16. ApplicationsApplications
 Today superconductivity is being applied to manyToday superconductivity is being applied to many
diverse areas such as: medicine, theoretical anddiverse areas such as: medicine, theoretical and
experimental science, the military, transportation,experimental science, the military, transportation,
power production, electronics as well as manypower production, electronics as well as many
other areas.other areas.

17. Magnetically Levitated TrainsMagnetically Levitated Trains
(MagLev)(MagLev)
The track are made with a continuous series ofThe track are made with a continuous series of
vertical coils of wire mounted inside. The wire invertical coils of wire mounted inside. The wire in
these coils is not a superconductor.these coils is not a superconductor.
As the train passes each coil, the motion of theAs the train passes each coil, the motion of the
superconducting magnet on the train induces asuperconducting magnet on the train induces a
current in these coils, making themcurrent in these coils, making them
electromagnets.The electromagnets on the trainelectromagnets.The electromagnets on the train
and outside produce forces that levitate the trainand outside produce forces that levitate the train
and keep it centered above the track.and keep it centered above the track.

18.  MagLev uses Electromagnetic Propulsion.MagLev uses Electromagnetic Propulsion.
 Trains are thrust forward by positively andTrains are thrust forward by positively and
negatively charged magnets.negatively charged magnets.
 The train floats on a cushion of airThe train floats on a cushion of air
eliminating friction.eliminating friction.

19. Application in MedicalApplication in Medical
MRI (Magnetic Resonance Imaging) scans produce detailed
images of soft tissues.
The superconducting magnet coils produce a
large and uniform magnetic field inside the
patient's body.

20. Application in PowerApplication in Power
 The cable configuration features a conductor
made from HTS wires wound around a flexible
hollow core.
 Liquid nitrogen flows through the core, cooling
the HTS wire to the zero resistance state.
 The conductor is surrounded by conventional
dielectric insulation. The efficiency of this design

21. Economic Impact ofEconomic Impact of
Superconducting EquipmentSuperconducting Equipment
• UtilitiesUtilities
• Higher density transmission & higherHigher density transmission & higher
economic productivityeconomic productivity
• Reduced environmental impactReduced environmental impact
• IndustrialIndustrial
More cost effective industrial processes:More cost effective industrial processes:
• Manufacturing & energy productionManufacturing & energy production
• Electrical storage, transmission and expansionElectrical storage, transmission and expansion
• TransportationTransportation
More cost effective electrical transportation:More cost effective electrical transportation:
• High Speed Rail & MAGLEV technologiesHigh Speed Rail & MAGLEV technologies
• Electric car / busElectric car / bus
• ShipShip

22. Worldwide Market forWorldwide Market for
SuperconductivitySuperconductivity
$0
$1,000
$2,000
$3,000
$4,000
$5,000
$6,000
$7,000
1997 2000 2003 2010
New Electronics Applications
New Large Scale Applications
Magnetic Resonance Imaging
Reseach & Technological Development
Millions

23. The dream - “Tomorrow’sThe dream - “Tomorrow’s
Superconducting World”Superconducting World”
*Energy saving: Power cable, motor, generator*Energy saving: Power cable, motor, generator
*Computing: 1000 times faster supercomputers*Computing: 1000 times faster supercomputers
*Information Technology: much faster, wider band*Information Technology: much faster, wider band
communicationcommunication
*levitated trains*levitated trains
*Magnetically launched space shuttle & moreover.*Magnetically launched space shuttle & moreover.

24. RefferencesRefferences
 ““Integrated Electronics”- Jacob Millman, Christos C. HalkiasIntegrated Electronics”- Jacob Millman, Christos C. Halkias
 ““Superconductivity Elementary”- Keshav N ShrivastavaSuperconductivity Elementary”- Keshav N Shrivastava
 ““Superconductivity Fundamentals & Applications”-Superconductivity Fundamentals & Applications”-
Prof. Dr. Werner Buckel, Prof. Dr. Reinhold KleinerProf. Dr. Werner Buckel, Prof. Dr. Reinhold Kleiner
WEBSITES:WEBSITES:
wikipediawikipedia
osun.org.comosun.org.com
teachers.web.cern.comteachers.web.cern.com
hyperphysics.eduhyperphysics.edu
nextbigfuture.comnextbigfuture.com

25. THANKS…THANKS…