Superconductivity and magnetic fields are like oil and water… they don’t mix. When it can, the superconductor will push out any magnetic fields from the interior in a process called the Meissner effect. It happens when a sample is cooled below its superconducting transition temperature, where it then cancels out its magnetic flux. What’s next? A superconductor. Now the fun really begins…
Even though scientists will claim otherwise, magnetism isn’t greatly understood. Because of electromagnetic induction (where an electric current is created when a conductor is moved through a magnetic field), a perfect conductor won’t change the magnetic flux when it cruises through at zero resistance. However, when cooled to the superconductor state the magnetic flux is expelled. Now we have perfect diamagnetism – where the interior magnetic field nears zero. At this point, if an external magnetic field is introduced, it will create an opposing magnetic field. This locks the two in place!
In the above video, a sample of yttrium barium copper oxide was cooled with liquid nitrogen to bring out its superconductive properties. The experiment shows it repelling the magnets which are loaded into the handheld unit. What’s unusual is that the sample can be angled, yet still held in place by the magnetic field. But keep on watching, because they’ve even created a “track” where the superconductor can be set into motion to either hover above – or below – the magnetic sensors.
While it might seem like just another science fair exhibit, think of the applications! You can almost envision mass transit gliding along carrying passengers inside a high temperature superconductor sourced vehicle… Or a warehouse where tow motors have become obsolete. Clean energy? Why not? Permanent magnets have been known to levitate. And when it comes to superconductors, electrons simply flow through in an orderly pattern without resistance. Why not “train” them?
Original News Source: Wired Science UK.