The purpose of this paper is to examine the materials, properties, and theory of superconductivity, a quantum phenomenon that occurs when a material is brought below a critical temperature and will conduct electricity without any resistance, the nearest model in nature to perpetual motion. According to Ecks (1990), Once current is applied to a superconducting material the current will continue in a closed lope without ever losing intensity. (Ecks, 1990) Superconductive materials can greatly vary in mechanics and materials. They are separated into Type 1 and Type 2 superconductors. All superconductors display the unique ability to repel magnetic fields, known as the Meissner effect.
According to Shachtman (2000), Superconductivity was discovered when a physicist, Heike Kamerlingh Onnes, when he developed the process to produce liquid helium and began testing the electrical properties of material at temperatures nearing absolute zero. Absolute zero is the coldest temperature that is theoretically attainable and is the basis of the Kelvin scale. Onnes first observed the phenomenon in mercury. A sample of mercury was cooled by liquid helium, and at the exact moment the temperature of the mercury reached 4.19K the resistance abruptly disappeared. (Shachtman, 2000)
According to Nave (2000), In Type I superconductors the phenomenon of zero resistance at low temperatures occurs in materials that are have some degree of conductivity under normal conditions. The properties of Type I superconductors were modeled successfully by the efforts of John Bardeen, Leon Cooper, and Robert Schrieffer in what is commonly called the BCS theory after the efforts of John Bardeen, Leon Cooper, and Robert Schrieffer in its understanding. (Nave, 2000)
Normal conduction occurs easily with materials such as copper, silver and gold because each contains just one electron in the outer shell that can easily be given up to carry an electrical current, but superconductivity appears to require more than free electrons. In superconductive materials a small fraction of electrons undergo a process known as Cooper pairing. At very low temperatures the passing of electrons through a crystal lattice causes the lattice to warp inwardly toward the electrons, creating sound packets termed phonons. These phonons, according to the theory, produce a channel of positive charge. (Ecks, 1990) According to Goldman (2000), Electrons that normally would repel one another, pair up in these channels of positive charge. The individual electrons cease to have meaning and occupy a single stable quantum state, known as a bose-einstein condensate. (Goldman, 2000)
According to Ecks (1990), Among most chemical elements, Cooper pairing is accomplished through vibrations at the molecular level within the crystal lattice structures of the atoms. Copper, silver, gold, and other non superconductive metals have tightly packed lattice structures that constrain the vibrations required for Cooper pairing....