A research team at the National High Magnetic Field Laboratory has reached a new world record in magnetic field generation, successfully testing a superconducting electromagnet to a field of 35.4 tesla. The magnet used a single, paper-thin, 100-meter-long strip of tape made with "YBCO," a superconducting ceramic composed of yttrium, barium, copper and oxygen. Tesla is the unit of measurement of magnetic field named in honor of Nikola Tesla, a famous 20th-century pioneer in the field of electromagnetism. One tesla is equal to 20,000 times the Earth's magnetic field.
The new results provide vital information for the next generation of high-field superconducting magnets. It's part of an ongoing effort to build a 32-tesla all-superconducting research magnet that could both reduce the cost of scientific experiments and make high-field research accessible to more scientific users. The 35.4 tesla field was achieved by "nesting" the YBCO coil inside a 31-tesla resistive magnet, with the "insert" YBCO coil supplying the additional 4.4 tesla.
Superconductors are materials that carry an electric current without resistance and can therefore conduct an electrical current without wasting energy through resistive heating. This, however, is a phenomenon that is only found at very low temperatures and for certain metals, alloys and ceramics. Superconductivity is an area of intense research interest, as it has current and potential applications in a wide range of technologies that directly impact peoples' lives. Electric power generation and transmission, transportation, and medical applications such as MRI all benefit, or have the potential to benefit, from research into superconductors.
Promising though they are, high-field superconducting materials such as YBCO are also frustratingly complex. They are brittle, still fairly expensive and in certain ways mysterious. YBCO is a member of the REBCO or rare-earth-barium-copper-oxide family of superconductors, brittle ceramics that represent a departure from the ductile alloy-type superconductors commonly used for magnetic fields up to 11 tesla (and for familiar applications such as MRIs).
The new high-field record was publicly announced on September 12 at the 22nd International Conference on Magnet Technology in Marseille, France. Conducted over the past year, this work represents "an important step on the way to generating the highest possible fields at low operating costs using superconducting technology," says team leader Dr. Ulf Peter Trociewitz, staff scientist at the Magnet Lab.
The tape was manufactured by New-York-based SuperPower, Inc., a world leader in developing commercially feasible high-temperature superconductors and related devices designed to enhance the capacity, reliability and quality of electric power transmission and distribution.
For more information about the technology behind this achievement, look for an article in Mag Lab Reports, Volume 18, Issue 4, to be published this fall.