الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
In 1911 K. Onnes discovered superconductivity [1]. Basically Superconductivity is defined as the flow of electric current without measurable resistance. This means the movement of the charge carriers without any friction with the materials constituents and hence no energy loss. The material begins to be a superconductor at a certain temperature called superconducting transition temperature Tc, and its resistance completely vanishes at zero resistivity temperature T0 as shown in Figure 1.1.Fig. 1.1. Superconducting properties (zero resistivity) for type-II superconductors
Besides the zero resistivity, superconductors have another important property which was discovered by Meissner and Ochsenfeld in 1933 [2] and called Meissner effect. This effect originates from the perfect diamagnetism of the superconductors. In other words, the superconducting materials exclude the magnetic flux lines and keep the magnetic induction inside it at zero. According to the magnetic field effect there are two types of superconductors, Type-I and type-II superconductors figure 1.2 (a), (b).