super conductivity
This article will explain to us the theory of superconductivity , the history of superconductivity , how its occurred , its application , meissener effect , the super fluidity and there are some links for websites to get more information about superconductivity
history of superconductor
Superconductivity was first discovered in 1911 by the Dutch physicist,Heike Kammerlingh Onnes. Onnes dedicated his scientific career to exploring extremely cold refrigeration. On July 10, 1908, he successfully liquified heliuem by cooling it to 452 degrees below zero Fahrenheit 4 kelvin or 4 K
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Superconductivity
is a phenomenon observed in several metals and ceramic materials. When these materials are cooled to temperatures ranging from near absolute zero ( 0 degrees Kelvin, -273 degrees Celsius) to liquid nitrogen temperatures ( 77 K, -196 C), their electrical resistance drops with a jump down to zero
The temperature at which electrical resistance is zero is called the critical temperature (Tc) and this temperature is a characteristic of the material as it is shown in the following table The critical temperature is known to be inversely proportional to the square root of the atomic mass
The cooling of the materials is achieved using liquid nitrogen or liquid helium for even lower temperatures
MEISSNER EFFECT
one of the properties of superconducting materials is the Meissner Effect. It was observed that as a magnet is brought near a superconductor, the magnet encounters a repulsive force. It can be said that the superconductor completely expels the magnetic field and behaves as a perfect diamagnet to get more information about meissner effect and supported by video
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This phenomenon was first observed in helium at a temperature below 2.17K. Helium at these low temperatures was seen to flow quite freely, without any friction, through any gaps and even through very thin capillary tubesit will keep on flowing forever - if there are no external forces acting upon it. Unlike all other chemical elements helium does not solidify when cooled down near absolute zero. Physicists explain this phenomenon by extremely weak attractive forces between the almost "perfectly round" atoms and by their rapid motion which is due to Heisenberg's Uncertainty Principle
Types of superconductors
the first type
Superconducting materials low temperature (Low temperature superconductor) and short (LTC), also called conventional superconducting materials such as mercury and characterized by low critical temperature
the second one
Materials high-temperature superconductors (High temperature superconductor) and short (HTC) and characterized by high critical temperature
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what about superconductor , superconductor , short notes about superconductor , history of superconductor , the theory of superconductor , types of superconductor , miessner effect , superfluidity of superconductor ,
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