Scientific terms can be confusing. DOE Explains offers straightforward explanations of key words and concepts in fundamental science. A cube of magnetic material levitates above a superconductor. The field of the magnet induces currents in the superconductor that generate an equal and opposite field, exactly balancing the gravitational force on the cube.
For this discovery, the liquefaction of helium, and other achievements, he won the Nobel Prize in Physics. Five Nobel Prizes in Physics have been awarded for research in superconductivity , , , , and Approximately half of the elements in the periodic table display low temperature superconductivity, but applications of superconductivity often employ easier to use or less expensive alloys.
For example, MRI machines use an alloy of niobium and titanium. Type-I materials remain in the superconducting state only for relatively weak applied magnetic fields. Above a given threshold, the field abruptly penetrates into the material, shattering the superconducting state.
Conversely, Type-II superconductors tolerate local penetration of the magnetic field, which enables them to preserve their superconducting properties in the presence of intense applied magnetic fields. This behaviour is explained by the existence of a mixed state where superconducting and non-superconducting areas coexist within the material.
Type-II superconductors have made it possible to use superconductivity in high magnetic fields, leading to the development , among other things, of magnets for particle accelerators. Research is underway to develop compounds that become superconductive at higher temperatures. Currently, an excessive amount of energy must be used in the cooling process making superconductors inefficient and uneconomical. S uperconductors come in two different flavors: type I and type II.
Type I Superconductors A type I superconductor consists of basic conductive elements that are used in everything from electrical wiring to computer microchips. The effect is a bit like a priority commuter lane on a busy motorway. Solo electrons get stuck in traffic, bumping into other electrons and obstacles as they make their journey. Paired electrons on the other hand are given a priority pass to travel in the fast lane through a material, able to avoid congestion. Superconductors have already found applications outside the laboratory in technologies such as Magnetic Resonance Imaging MRI.
Superconducting magnets also made possible the recent detection of the Higgs Boson at CERN , by bending and focusing beams of colliding particles. One interesting and potentially useful property of superconductors arises when they are placed near a strong magnet. The magnetic field causes electrical currents to spontaneously flow on the surface of a superconductor, which then give rise to their own, counteracting, magnetic field.
The effect is that the superconductor dramatically levitates above the magnet, suspended in the air by an invisible magnetic force. What prevents more widespread use of these materials is the fact that the superconductors we know about operate only at very low temperatures.
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