super conductivity

OW YEAH!!!!!

ALFRED COMES BACK!

wew, 

I think blogging is easy... But, in fact It's really hard

After 2 days (or more) thinking a new topic, 

now, 

ALFRED COMES WITH NEW TOPIC.......

(HAHAHAHAHAHAHA)

Ok, 

WE START NOW...

 
Hm...

Did you ever heard "SUPER CONDUCTIVITY"??

Super conductivity is a phenomenon occuring in a certain materials generally at very low temperatures, characterized by exactly zero electrical resistance and the exclusion of the interior magnetic field <Meissner effect>

The Meissner effect (1933, Walther Meissner and Robert Ochsenfeld) is the expulsion of a magnetic field from a superconductor. Walther Meissner and Robert Ochsenfeld discovered the phenomenon in 1933 by measuring the magnetic field distribution outside tin and lead samples. The samples, in the presence of an applied magnetic field, were cooled below what is called their superconducting transition temperature. Below the transition temperature the samples cancelled all magnetic field inside, which means they became perfectly diamagnetic. They detected this effect only indirectly; because the magnetic flux is conserved by a superconductor, when the interior field decreased the exterior field increased. The experiment demonstrated for the first time that superconductors were more than just perfect conductors and provided a uniquely defining property of the superconducting state.

There is not just one criterion to classify superconductors. The most common are:
*By their physical properties: they can be Type I (if their phase transition is of first order) or Type II (if their phase transition is of second order).
*By the theory to explain them: they can be conventional (if they are explained by the BCS theory or its derivatives) or unconventional (if not).
*By their critical temperature: they can be high temperature (generally considered if they reach the superconducting state just cooling them with liquid nitrogen, that is, if Tc > 77 K), or low temperature (generally if they need other techniques to be cooled under their critical temperature).
*By material: they can be chemical elements (as mercury or lead), alloys (as niobium-titanium or germanium-niobium), ceramics (as YBCO or the magnesium diboride), or organic superconductors (as fullerenes or carbon nanotubes, which technically might be included between the chemical elements as they are made of carbon).

THAT'S ALL ABOUT SUPERCONDUCTOR.... I MAKE IT SHORT BECAUSE TOO MANY TO EXPLAIN ABOUT THIS (ESPECIALLY THE MEISSNER EFFECT)

HAHAHA.....

SEE YA ....

ALFRED & YAHA