Fritz Walther Meissner: Difference between revisions
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== See also == | == See also == | ||
===Further Reading=== | |||
*{{cite book |author=[[Fritz Wolfgang London]] |title=Superfluids |series=Structure of matter series |volume=1 |contribution=Macroscopic Theory of Superconductivity |year=1950 |oclc=257588418}}. Revised 2nd edition, Dover (1960) ISBN 978-0-486-60044-4. By the man who explained the Meissner effect. pp. 34–37 gives a technical discussion of the Meissner effect for a superconducting sphere. | |||
===External links=== | ===External links=== | ||
Revision as of 22:09, 5 December 2015
created by dcho39
Personal Life
Fritz Walther Meissner was born in Berlin, Germany on December 16, 1882 to Waldemar Meissner and Johanna Greger. He was educated at the Technical University of Berlin, studying physics and mechanical engineering; his supervisor was Max Planck. After, he attended the Physikalisch-Technische Bundesanstalt in Berlin. In 1926, he became chair in technical physics at the Technical University of Munich. He also later became the president of the Bavarian Academy of Sciences and Humanities. Sadly, Meissner lived lonely for the last few years until his death in 1974, with only his two dogs to accompany him.
Scientific Contributions
Meissner Effect
Aided by fellow German physicist Robert Ochsenfeld, Meissner discovered this scientific phenomenon in 1933. The Meissner effect is when a superconductor expels all magnetic fields from its interior during its transition to the superconducting state. This finding was actually done so indirectly. The two scientists were observing how the magnetic flux is conserved by a superconductor. They found that their sample of tin and lead were cooled below their critical, or superconducting transition, temperature when in the presence of an applied magnetic field. At this point, almost all interior magnetic fields were neutralized.
Explanation
The Meissner effect was given a phenomenological explanation by the brothers Fritz and Heinz London, who showed that the electromagnetic free energy in a superconductor is minimized provided
where H is the magnetic field and λ is the London penetration depth. It is also called the London equation.
It states the the magnetic field weakens substantially as you go from the surface to the interior of the superconductor.
This is due to the superconductor creating electric currents at the surface that will cancel the magnetic field. This effect continues for a very long time as the cancellation is not dependent on time, which leads the superconductor to be thought of as always expelling magnetic fields.
Connectedness
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History
Meissner's discovery of the Meissner effect led to Friz and Heinz London developing the theory of superconductivity. It explained the Meissner effect as well as how transport could have no resistance, and also paved the way for predictions of superconductivity to be produced.
See also
Further Reading
- Template:Cite book. Revised 2nd edition, Dover (1960) ISBN 978-0-486-60044-4. By the man who explained the Meissner effect. pp. 34–37 gives a technical discussion of the Meissner effect for a superconducting sphere.