Where Does the Real Where Does the Real World Meet World Meet

Superconductors?Superconductors?Saturday Morning PhysicsSaturday Morning Physics

December 13, 2003December 13, 2003

Dr. Sa-Lin Cheng BernsteinDr. Sa-Lin Cheng Bernstein

Type I SuperconductorsType I Superconductors

T

H

Hc

Tc

Phase Diagram

Image courtesy: Joseph Bernstein © Akira Tonomura (Hitachi, Japan)

Theory: BCS & Ginzburg-Landau

Type II SuperconductorType II Superconductor

T

H

Hc1

Tc

Phase Diagram

Hc2

Image courtesy: Joseph Bernstein

© Akira Tonomura (Hitachi, Japan)

Theory: Abrikosove & Ginzburg-Landau

When applying currentWhen applying current

Lorentz force pushes vortices (Flux motion) Lorentz force pushes vortices (Flux motion)

Dissipation of energy

Resistance

Increase of temperature

Quench!!!

Superconducting Superconducting state:state: T < TT < Tcc

H < HH < Hc2c2

J < JJ < J cc

Critical Surface Phase DiagramCritical Surface Phase Diagram

Vortex PinningVortex Pinning To increase JcTo increase Jc Artificial pinning Artificial pinning

centers:centers:

How do vortices move?How do vortices move?– Avalanche vortex movies Avalanche vortex movies – See first time (1993): See first time (1993):

Akira Tonomura using Akira Tonomura using transmission electron transmission electron microscopemicroscope

A. Bezryadin et al.© Phys. Rev. B 53, 8553 (1996)

http://www.howstuffworks.com/power.htm

Power Transmission Power Transmission 2001: Copenhagen, Denmark2001: Copenhagen, Denmark

– high-temperature superconducting (HTS)high-temperature superconducting (HTS)– only 30 meters longonly 30 meters long

High cost!!High cost!!

Power Transmission in USAPower Transmission in USA 2001: Detroit, USA2001: Detroit, USA

– Detroit Edison at the Frisbie Substation Detroit Edison at the Frisbie Substation – three 400-foot HTS cablesthree 400-foot HTS cables– 100 million watts of power100 million watts of power

http://www.ornl.gov/sci/fed/applied/htspa/cable.htm

Superconducting Magnet Superconducting Magnet Normal electromagnet: Normal electromagnet:

1 Tesla (= 10000 G)1 Tesla (= 10000 G) Argonne bubble Argonne bubble

chamber:chamber:– Magnetic field = 1.8 TMagnetic field = 1.8 T– Alloy of niobium and Alloy of niobium and

titanium (Nbtitanium (Nb33Ti wire)Ti wire)– Tc = 10 KTc = 10 K– Hc2 = 15 THc2 = 15 T

© Argonne National Laboratory

Maglev TrainsMaglev Trains ““Maglev”: Maglev”: MagMagnetic netic LevLevitationitation

MLX01

http://www.rtri.or.jp/rd/maglev/html/english/maglev_frame_E.html

Working ModelWorking Model

National Institute of Technology and Standards

How does it work?How does it work?

http://www.acmaglev.com/technology.htm

http://www.acmaglev.com/technology.htm© John Wiley & Sons, Inc.

© John Wiley & Sons, Inc.

The Real DealThe Real Deal

http://www.visionengineer.com

430 km/h = 267.2 mph

American MaglevAmerican Maglev Atlanta ProjectAtlanta Project Florida ProjectFlorida Project Old Dominion University ProjectOld Dominion University Project Virginia ProjectVirginia Project Edgewater ProjectEdgewater Project Charlotte ProjectCharlotte Project

MHD PropulsionMHD Propulsion MHD = MHD = mmagnetoagnetohhydroydroddynamicynamic First MHD ship: Yamato 1First MHD ship: Yamato 1

http://voyager55.cool.ne.jp/norimono/ship/public.html© John Wiley & Sons, Inc.

TevatronTevatron 19831983 Radius = 6.3 kmRadius = 6.3 km 1000 superconducting 1000 superconducting

magnets (Nbmagnets (Nb33Ti wires)Ti wires) Protons + AntiprotonsProtons + Antiprotons Energy = 1000 GeV Energy = 1000 GeV

(=1 TeV)(=1 TeV) vv ~ 200 mph slower ~ 200 mph slower

than speed of lightthan speed of light

The Circular TrajectoryThe Circular Trajectory F is directed toward the F is directed toward the

center of the circular pathcenter of the circular path

F v⊥v v

mB v

qr=

© John Wiley & Sons, Inc.

MRIMRI Magnetic Resonance Imaging

http://www.upstate.edu/mrilab/equipment/equipment.htm http://www.etch.com/mri.cfm

An ExampleAn Example

Human body: fat and waterHuman body: fat and water Approximately 63% hydrogen atomsApproximately 63% hydrogen atoms NMR signal from the hydrogen nuclei NMR signal from the hydrogen nuclei

Image courtesy: Seth Blumberg

Spin of A ProtonSpin of A Proton Can be thought of as a small Can be thought of as a small

magnetic field magnetic field Spin of a proton = ½Spin of a proton = ½ Spin of a hydrogen nucleus = ½Spin of a hydrogen nucleus = ½

http://www.cis.rit.edu/htbooks/mri/inside.htm

P

Energy LevelsEnergy Levels

Low energy state High energy state

http://www.cis.rit.edu/htbooks/mri/inside.htm

TransitionsTransitions The energy of the photon must exactly The energy of the photon must exactly

match the energy difference between the match the energy difference between the two states two states

Frequency=fhigh lowE E E= −

http://www.cis.rit.edu/htbooks/mri/inside.htm

Resonance FrequencyResonance Frequency f = resonance frequency f = resonance frequency

E hf=

Energy of photon

Plank’s constant

Frequency

http://www.cis.rit.edu/htbooks/mri/inside.htm

Probe EnergyProbe Energy B = magnetic fieldB = magnetic field γγ = gyromagnetic ratio (H: 42.58 MHz/T) = gyromagnetic ratio (H: 42.58 MHz/T)

f Bγ=

E h Bγ=http://www.cis.rit.edu/htbooks/mri/inside.htm

Detect TumorsDetect Tumors The signal in NMR spectroscopy: energy The signal in NMR spectroscopy: energy

difference (absorption & emission)difference (absorption & emission) Raymond Damadian:Raymond Damadian:

Nuclear magnetic relaxation times of Nuclear magnetic relaxation times of tissues and tumors differed (1971)tissues and tumors differed (1971)

Paul Lauterbur and Peter Mansfield:Paul Lauterbur and Peter Mansfield:2003 Nobel Prize in Medicine 2003 Nobel Prize in Medicine

SMESSMES SSuperconducting uperconducting MMagnetic agnetic EEnergy nergy

SStoragetorage

http://www.epri.com/journal/details.asp?id=349

Neutron Stars (NS)Neutron Stars (NS)

Stellar corpses– result from collapse of massive star– big ball of neutrons (n) with some protons (p+)

and electrons (e-) What opposes gravity?

– density so high, n, p+, e- packed as tightly as possible

– degenerate matter supported by degeneracy pressure

Crab Nebula (M1) Here!

Cassiopeia-A:

Image courtesy B. T. Koralesky, U. Minnesota

Mono-frequency Radio

Here!

NS Physical PropertiesNS Physical Properties

PropertyProperty NSNS SunSun

Mass [kg] 3.0 × 1030 2.0 × 1030

Radius [m]Radius [m] 1.0 × 1004 7.0 × 1008

Density [kg/Density [kg/m3] 7.2 × 1017 1.4 1.4 × 1003

Factor Different

1.5

1/70,000

500 Trillion

g [m/sg [m/s22]] 2.0 2.0 × 1012 9.89.8 200 Billion

world pop. in 1-cm3 box

Object dropped from 1m has v ≈ 4.5×106 mph at surface

Orbit Near the SurfaceOrbit Near the Surface

by Robert Nemiroff, Michigan Tech. Univ.

Average density of NS is about 3 times the density of an atomic nucleus

⇒ nuclei dissolve into free n and p+

get n Cooper pairs and p+ Cooper pairs

What’s Inside a NS?What’s Inside a NS?

SUPERFLUID! SUPERCONDUCTO

R!

http://www.stormpages.com/swadhwa/stellarevolution/lecture20.htm

Inside A Neutron StarInside A Neutron Star

Room-Temp. SuperconductivityRoom-Temp. Superconductivity Carbon nanotubes Carbon nanotubes ? ? ?? ? ?

Image: Dr Chris Ewels

AcknowledgementAcknowledgement The audienceThe audience Demo lab (Warren, Mark, and Harminder)Demo lab (Warren, Mark, and Harminder) Prof. Franco NoriProf. Franco Nori Seth Blumberg Seth Blumberg Joseph BernsteinJoseph Bernstein