In a conducting material, the electrons move freely, while in an insulating material they do not. The atoms and molecules of an insulator hold tightly to their electrons. Conductors are materials where some electrons are free of atomic bonds and flow freely through the material. A normal conductor supports the flow of current. Good electrical conductors are typically also good thermal conductors, so electrical systems lose some energy to the generation of heat.

Semiconductor

Semiconductors are materials which conduct electricity when some energy is given to them. Materials can be classified into conductors, insulators and semiconductors based on their capacity to conduct electricity. Conductors easily conduct electricity whereas an insulator is a bad conductor of electricity. Conduction of electricity depends on the energy gap between the valence band of an atom and the conduction band. The valence band is the highest energy level occupied by electrons that are still bound to an atom, and the conduction band is the next higher energy level after the valence band that electrons can occupy. Electrons in the conduction band are not bound to a particular atom.

The gap between the valence band and the conduction band is highest in insulators and lowest in conductors; whereas in semiconductors this gap is typically around 1ev. Elemental semiconductors are semiconductors where each atom is of the same type, such as Germanium or Silicon. These atoms are bound together by covalent bonds, so that each atom shares an electron with its nearest neighbor, forming strong bonds. Semiconductors are used in transistors (and therefore computers); light emitting diodes, solar cells, light sensors and lasers.

The semiconductor chip brought about a fundamental revolution in the advancement of electronics technology. The semiconductor manufacturing process begins with one of the most common elements on earth, silicon. Silicon must be 100% purified in order to be used for chip manufacturing. The pure silicon is then heated until it reaches a molten state and a perfectly structured silicon ?seed? is then lowered into the molten silicon. The chemical properties of the molten silicon allow a chemical bond to be formed with the seed and a long ingot of solid silicon can slowly be pulled from the silicon as its cools and solidifies around the seed. When the process is complete, the finished ingot exactly mimics the physical characteristics of the original seed material. The ingot is then carefully sawed into thin wafers the diameter of the ingot, most commonly 200 mm (8-inches) or 300 mm (12-inches) across.

Superconductors

A compound or an alloy made up of elements which conduct electricity with zero resistance at certain temperatures is called a superconductor. Resistance can be measured by passing current into the conductor and applying voltage across it. Using Ohm's law, V=IR, we can find the resistance of the conductor." A high temperature superconductor can conduct electricity as high as 138K and a low temperature superconductor can conduct electricity as low as -200K. Superconductivity occurs in a wide range of materials like tin and aluminium, Caluminum, metal alloys, some semiconductors and certain ceramic products with traces of copper in it. It does not occur in elements such as gold and silver.
A superconductor is a material that supports current flow, but does not have much associated heat loss (loss of energy due to heating the material and surroundings). Particle accelerators are large consumers of power, and it can be helpful in some cases to build components with superconducting material to reduce thermal loss. Accelerating cavities and magnets been built with superconducting materials.

Superconducting materials such as niobium-titanium and niobium-tin are used to make coil windings for superconducting magnets. The superconductors are made such that a large number of filaments will fit into the copper mesh. The solid copper gives mechanical stability and provides a path for the large currents in case the superconducting state is lost. Niobium-tin and niobium-titanium superconductors can withstand high magnetic fields and must be cooled in liquid Helium. The critical temperature and critical magnetic field for a niobium- titanium superconductor are 10K and 15 tesla respectively whereas the critical temperature for niobium-tin alloy in 18K.

Low Temperature Superconductors

Low Temperature Superconductors (LTS) typically refer to niobium-based alloys such as Nb3Sn and Nb3Al. Here temperature means the temperature below which the superconductor must be cooled in order for it to become superconducting. For LTS that temperature is usually well below 20 K (-253 °C). Niobium alloy has become the dominant commercial superconductor because it can be economically manufactured in a ductile form which is needed for high critical current. Similarly Nb3Sn based strand, can be manufactured into strong composites in km lengths and microstructures that promote high critical current densities. These superconductors are often termed "technical superconductors" because of their applicability to engineering tasks.