New research from the Brookhaven National Laboratory has revealed that magnetic excitations, quantum waves believed by many to regulate high-temperature superconductors, exist in both non-superconducting and superconducting materials.
Intrinsic inefficiencies plague current systems for the generation and delivery of electricity, with significant energy lost in transit. High-temperature superconductors (HTS)—uniquely capable of transmitting electricity with zero loss when chilled to subzero temperatures—could revolutionize the planet’s aging and imperfect energy infrastructure, but the remarkable materials remain fundamentally puzzling to physicists. To unlock the true potential of HTS technology, scientists must navigate a quantum-scale labyrinth and pin down the phenomenon’s source.
Now, scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and other collaborating institutions have discovered a surprising twist in the magnetic properties of HTS, challenging some of the leading theories. In a new study, published online in the journal Nature Materials on August 4, 2013, scientists found that unexpected magnetic excitations—quantum waves believed by many to regulate HTS—exist in both non-superconducting and superconducting materials.
“This is a major experimental clue about which magnetic excitations are important for high-temperature superconductivity,” said Mark Dean, a physicist at Brookhaven Lab and lead author on the new paper. “Cutting-edge x-ray scattering techniques allowed us to see excitations in samples previously thought to be essentially non-magnetic.”
On the atomic scale, electron spins—a bit like tiny bar magnets pointed in specific directions—rapidly interact with each other throughout magnetic materials. When one spin rotates, this disturbance can propagate through the material as a wave, tipping and aligning the spins of neighboring electrons. Many researchers believe that this subtle excitation wave may bind electrons together to create the perfect current conveyance of HTS, which operates at slightly warmer temperatures than traditional superconductivity.
“Proving or disproving this hypothesis remains one of the holy grails of condensed matter physics research,” Dean said. “This discovery gives us a new way to evaluate rival theories of HTS.”