Demonstration of the Meissner
Effect Using Superconducting
Y2BaCuO5 (YBCO)
Michael Moore
College of the Redwoods
Superconducting Magnet Program
Lawrence Berkeley National Lab
Y2BaCuO5 is a High Temperature
Superconductor
The critical temperature(Tc) is the temperature at which a material
becomes superconductive
Tc(k)
160
140
Hg0.8TI0.2Ba2Ca2Cu2O8.33
120
Bi1.6Pb0.6Sr2Ca2Sb0.1Cu3Oy
100
Bi2Sr2CaCu2O9
80
60
LN-80 K
LHe-4.2 K
YBa2CuO5
(La,Sr,Ca)3Cu2O6
40
Nb3Si
20
Nb3Sn
0
Hg
1
Superconductors
YBCO is a Type II
Superconductor
Resistance
• Type I has a much sharper
Non-superconductive metals
transition to
superconductivity and
Type II
exhibits perfect
diamagnetism
• Type II allows flux
Type I
pinning and has a higher
Tc
0Ω
• The Meissner Effect only
0K
Tc
occurs in Type II
Superconductivity Creates
Diamagnetism
The surface of the YBCO assumes the same Flux value as the external flux
from the magnets and allows none of it to enter the YBCO’s interior.
Because Like poles repel each other, the YBCO is levitated
Impurities in the YBCO Causes
Flux Pinning
Diamagnetism in
superconducting material
Impurities(non-superconducting
materials) pin flux lines in flux
lattice votices
The Meissner Effect is a Combination
of Diamagnetism and Flux Pinning
Permanent
Magnet
Type II
superconductor
The classic Meissner Effect demonstration
Flux Density and Magnetic Flux
Lines of Track Configuration
Low
Density
Flux Lines
Permanent Magnets
High
Density
The YBCO will only move along
the track
YBCO
•Flux Pinning will only allow
flux lines of the same
value to enter the
vortexes
•Since the values only stay the
same in a line parallel
to the track, the YBCO
only moves in that
direction
Liquid Nitrogen Cools the YBCO
Below its Tc
Liquid Nitrogen
YBCO
When the LN boils away, the YBCO stays
superconducting for ≈ 3 minutes
Acknowledgements
I would like to thank my mentor, Stephen Gourlay for his guidance and support
on this project, Zach Radding for Design works’ involvement, Kathleen Weber
for helping me get used to lab culture, Ron Scanlen, Dan Dietderich, GianLuca
Sabbi and Shlomo Caspi for their help with the properties of superconductors,
Jim Swithwick for computer assistance, Alan Lietzke for putting up with my
love for gauss meters, Jim Swanson, Hugh Higley, Scott Bartlett, Ray Hafalia,
Roy Hannaford, and Nate Liggens who all helped immensly with tools and
inspiration. A big thanks to Goli Modeste who took the time to machine parts
for me. Jon Zbasnik was a great inspiration, and Dawn Faessler and Tom
Martin were great friends that made work more enjoyable. Thanks to Sara
Mattafirri for sharing her space with me. I would also like to thank Laurel
Egenberger, Susan Aberg and everyone at CSEE who made this summer a
fulfilling one. Last but not least, thanks to the U.S. Department of Energy,
Office of Science. The research described here was performed at the Lawrence
Berkeley National Laboratory and funded by the Department of Energy Office
of Science under Contract No. DE-AC03-76SF00098.