Soon after Kamerlingh Onnes discovered superconductivity, scientists began dreaming up practical applications for this strange new phenomenon. Powerful new superconducting magnets could be made much smaller than a resistive magnet,because the windings could carry large currents with no energy loss. Generators wound with superconductors could generate the same amount of electricity with smaller equipment and less energy. Once the electricity was generated it could be distributed through superconducting wires. Energy could be stored in superconducting coils for long periods of time without significant loss.

The recent discovery of high temperature superconductors brings us a giant step closer to the dream of early scientists. Applications currently being explored are mostly extensions of current technology used with the low temperature superconductors. Current applications of high temperature superconductors include; magnetic shielding devices, medical imaging systems, superconducting quantum interference devices (SQUIDS), infrared sensors, analog signal processing devices, and microwave devices. As our understanding of the properties of superconducting material increases, applications such as; power transmission, superconducting magnets in generators, energy storage devices, particle accelerators, levitated vehicle transportation, rotating machinery, and magnetic separators will become more practical.

The ability of superconductors to conduct electricity with zero resistance can be exploited in the use of electrical transmission lines. Currently, a substantial fraction of electricity is lost as heat through resistance associated with traditional conductors such as copper or aluminum. A large scale shift to superconductivity technology depends on whether wires can be prepared from the brittle ceramics that retain their superconductivity at 77 K while supporting large current densities.

The field of electronics holds great promise for practical applications of superconductors. The miniaturization and increased speed of computer chips are limited by the generation of heat and the charging time of capacitors due to the resistance of the interconnecting metal films. The use of new superconductive films may result in more densely packed chips which could transmit information more rapidly by several orders of magnitude. Superconducting electronics have achieved impressive accomplishments in the field of digital electronics. Logic delays of 13 picoseconds and switching times of 9 picoseconds have been experimentally demonstrated. Through the use of basic Josephson junctions scientists are able to make very sensitive microwave detectors, magnetometers, SQUIDs and very stable voltage sources.

The use of superconductors for transportation has already been established using liquid helium as a refrigerant. Prototype levitated trains have been constructed in Japan by using superconducting magnets.

Superconducting magnets are already crucial components of several technologies. Magnetic resonance imaging (MRI) is playing an ever increasing role in diagnostic medicine. The intense magnetic fields that are needed for these instruments are a perfect application of superconductors. Similarly, particle accelerators used in high-energy physics studies are very dependant on high-field superconducting magnets. The recent controversy surrounding the continued funding for the Superconducting Super Collider (SSC) illustrates the political ramifications of the applications of new technologies.

New applications of superconductors will increase with critical temperature.Liquid nitrogen based superconductors has provided industry more flexibility to utilize superconductivity as compared to liquid helium superconductors. The possible discovery of room temperature superconductors has the potential to bring superconducting devices into our every-day lives.

High-temperature superconductors are recent innovations from scientific research laboratories. New commercial innovations begin with the existing technological knowledge generated by the research scientist. The work of commercialization centers on the development of new products and the engineering needed to implement the new technology. Superconductivity has had a long history as a specialized field of physics. Through the collaborative efforts of government funded research, independent research groups and commercial industries, applications of new high-temperature superconductors will be in the not so distant future. Time lags however, between new discoveries and practical applications are often great. The discovery of the laser in the early 60's has only recently been appreciated today through applications such as laser surgery, laser optical communication, and compact disc players. The rapid progress in the field of superconductivity leads one to believe that applications of superconductors is limited only by one's imagination and time.

The table on the next page shows both present and potential applications of superconductors. As you can see application of superconductors is only just beginning.


Application                                 Current     Emerging

            magnetic resonance imaging         X           
            biotechnical engineering                       X

            SQUIDs                              X
            transistors                                     X
            Josephson Junction devices                      X
            circuitry connections                           X
            particle accelerators               X
            sensors                             X

            separation                          X
            magnets                             X
            sensors and transducers                          X
            magnetic shielding                               X

      Power Generation               
            Motors                                            X
            Generators                                        X
            Energy Storage                                    X
            Transmission                                      X
            Fusion                                            X
            Transformers and Inductors                        X

            Magnetically levitated vehicles                   X
            Marine propulsion                                 X

Date posted 04/01/96 (ktb)