Superconductivity is a phenomenon in which the material has zero resistivity when it is subjected to certain characteristic temperature. This phenomenon is only observed in certain materials. In terms of theory, if the material is a superconductor, it cannot support a magnetic field inside it. This state of material only exists below the critical temperature, reaching which if often quite difficult – less than 10 Kelvin. However, once the material has achieved this state, its resistance falls abruptly to zero. More recently, some high temperature superconductors have been discovered, which can attain the zero resistance state at temperatures as high as 130 K.
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In reality, the resistance of a conductor depends on the availability of the free electrons, which are abundant in elements like coppers, iron etc. As discussed earlier, in order to attain superconductivity, or high conductivity for that matter, a lot of external factors are required, the biggest one being the sub critical temperatures. That is not the case in most of the simulation scenarios. So, in order to simplify the calculations, an assumption of perfect conductor is made.
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