A superconductor is defined as a material that has zero electrical resistance and can expel all magnetic fields lines from within the material itself when it is cooled below a certain critical temperature. In a normal conductive material such as copper, the electrons inside the wire bump into one another causing collisions which then creates heat which contributes to a sizable amount of energy loss within the wire. A superconductor has no interior magnetic fields and therefore no resistance for the electrons which prevents the electrons from colliding with one another and heating up the wire causing energy loss. Superconductors are able to hold a charge for a near infinite amount of time making them highly sought after for numerous industries.
There are two different kinds of superconductors as well, there are type I and type II superconductors. A type I superconductor has only one critical temperature and upon reaching this certain temperature, the internal resistance immediately drops to zero and all magnetic fields are expelled from the material. A type II super conductor has two separate critical temperatures, the colder of which acts just like a type I superconductor where resistance goes to zero and magnetic field lines are expelled. When the temperature of the material is above the warmer of the two temperatures it acts like a normal material however in the region between the two temperatures the material can behave like a superconductor and a normal material in which resistance is extremely low yet it still allows for some magnetic field lines to penetrate its surface. The limited penetration of the field lines is what allows type II superconductors to be locked in place in mid air and appear to be levitating.
The expulsion of magnetic field lines from the interior of a superconductor as it approaches temperatures allowing for super conductivity is what is known as the Meissner Effect. The superconductor is able to expel the magnetic fields by establishing an electrical current near the surface of the material. The magnetic field created by the current on the surface cancels out the magnetic field within the material thus causing it to become a superconductor with zero resistance and no internal magnetic fields.
There are two different kinds of superconductors as well, there are type I and type II superconductors. A type I superconductor has only one critical temperature and upon reaching this certain temperature, the internal resistance immediately drops to zero and all magnetic fields are expelled from the material. A type II super conductor has two separate critical temperatures, the colder of which acts just like a type I superconductor where resistance goes to zero and magnetic field lines are expelled. When the temperature of the material is above the warmer of the two temperatures it acts like a normal material however in the region between the two temperatures the material can behave like a superconductor and a normal material in which resistance is extremely low yet it still allows for some magnetic field lines to penetrate its surface. The limited penetration of the field lines is what allows type II superconductors to be locked in place in mid air and appear to be levitating.
The expulsion of magnetic field lines from the interior of a superconductor as it approaches temperatures allowing for super conductivity is what is known as the Meissner Effect. The superconductor is able to expel the magnetic fields by establishing an electrical current near the surface of the material. The magnetic field created by the current on the surface cancels out the magnetic field within the material thus causing it to become a superconductor with zero resistance and no internal magnetic fields.