100 Years of Superconductivity, Professor
James Annett
BRLSI
(IOP South West Branch) 6th
May 2011
Prof
Annett graduated from Cambridge
and completed post doctorate studies in Illinois
before moving to Bristol
in 1994 as a lecturer.
1897 JJ Thompson discovered electron
1900 Mark Plank quantum physics
1905 Albert Einstein and the photo-electric
effect, special relativity and Brownian motion
1908 H Kamerlingh Onnes liquefied helium at 3
degrees Kelvin
1987 James Dewar liquefied hydrogen
Superconductors
expel ALL the magnetic field, they
are perfect diamagnets.
Þ
Electron-lattice
attraction near Fermi momentum (Energy level)
Þ
Leads
to Cooper Pairs of electrons
Þ
Near
band gap energy (The conduction band electrons are all paired up)
‘Gauge
symmetry’:
Ø Not as would be expected from
nature
Ø Nature NOT symmetrical (!?!)
o Leads to theorized Higgs boson
1986 the
Tc (critical temperature for superconductivity) first breached the theorized
limit of 30K from BCS theory (new
types of superconductor invented).
[Random
thought: Bionic implant for the eye to assist in eye focussing.]
Binding
energy for superconductors attached to magnets
Ø (There are three different
mechanisms depending on type of superconductor.)
o doping diagram of
superconductivity being affected by alloy being doped
Uses of
superconductors in the current world:
·
Superconducting
power grid
o High density of current
o REAL TECHNOLOGY
·
Superconducting
motors
·
Computing
What to
expect?
·
Possibly
reach room temperature superconducting
[Random
thought: People must intimidate each other for having good eye-sight in the
West generally but this trend is now being reversed and it can be seen that
people wearing glasses are now facing the threat of violence for being
short-sighted]
The optical properties of superconductors
are mainly in the infrared so far (via interaction with Cooper pairs of
electrons for bullshit example).
·
Possible
application in bionic eye implant as a focussing sensor for the eye.
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