Levitation, the ability to appear to defy gravities bonds, has long fascinated humanity. From flying carpets to flying nuns it has long been part of our culture.There is a modern take on this ancient story as well, Superconducting Levitation. Seemingly able to cancel out gravity and allow objects to levitate, it seems to be the answer to giving us mere mortals at least one of superman’s powers, the ability to fly. Unfortunately superconductors don’t cancel out gravity and we will never fly under our own power, undies on the outside maybe. Instead the levitating effect called Quantum Levitation uses a number of the unusual properties of superconductors to create the effect.All current superconductors need the cold to enter their superconducting phase. In this phase electrons are able to move about without any resistance, power loss or heat generated, which is typical for most wires or electronics that use ordinary conductors. Many different materials exhibit superconducting properties, from metals to the latest ceramics most substances have been tested for these properties. Ceramics are the latest so called high temperature superconductors. High temperature in the world of superconductors means -200 degrees Celsius. Cold enough to be cooled by the cheaper liquid nitrogen instead of liquid helium. Once a material is cooled sufficiently and enters its superconducting phase it’s electrical and magnetic properties change. Electricity looses all resistance and magnetic fields are forced to go around a superconductor.

The demonstration by the superconductivity group of Tel Aviv University involve a thin sapphire crystal with a ceramic superconductor coated on top levitating above what is perhaps the coolest coffee table ever. Built into the rim of the circular coffee table is a ring of powerful permanent magnets. Once the Sapphire ceramic superconductor is in phase it is able to be locked into position and spun around the edge of the table. The .5 micron thick layer of ceramic only becomes a superconductor once it is cooled below -200 degrees Celsius. Once it is switched into superconducting phase defects in the sapphire crystal cause weakness in the superconductor, at these weak points the magnetic field can penetrate the superconductor. Expose the superconductor to a magnetic field and the superconductor will resist as best it can. The few points the magnetic field does penetrate are locked or pinned by the superconductor, freezing the superconductor exactly where it is, this is flux pinning or quantum pinning.
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Researchers at Ithaca College NY have also put together some flux pinning magic. Demonstrated using what might become every young lads favorite new toy, the quantum levitating slot car set, is this what Scalextric will look like in 10 years? Based on the same principles as Prof. Deutchers levitation work using a superconductor and the flux pinning to both levitate and guide a superconductor or puck around the figure eight track. The track uses electromagnets instead of rare earth permanent magnets which allows the voltage to be used to alter the speed the puck can travel around the track., these magnets are arranged 3 magnets wide in a figure 8 track roughly the same size as a child’s slot car set. The maglev system actually employs a few parts from a slot car set to accelerate the puck around the track.
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Not all superconductors are created equal. In the cold world of superconductors they are grouped into two types, Type 1 and Type 2. Turns out that superconductors and magnetic fields don’t much like each other. Superconductors will try to exclude any magnetic field from it’s interior, the Meissner Effect. A Type 1 superconductor is a perfect superconductor that is able to completely exclude magnet fields from entering its mass and when the magnetic field passes the superconductors strength the entire mass will become resistive, loosing its superconducting properties all at once. Type 2 superconductors are not as perfect as Type 1, with the imperfections allowing the magnetic fields to penetrate the superconductor. When the Type 2 superconductor is over-powered by a magnet field it will shift in parts, with some internal parts becoming resistive and some staying as superconductors. This middle ground is called the Second order phase transition.
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Superconductors are the most powerful electromagnets available, so it is no surprise that they are finding many commercial uses. Maglev trains are the most famous of these uses but they’re also found in in medical equipment, particle accelerators and medical sensors.
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Quantum Levitation is one of the many visually stunning demonstrations of quantum mechanics and superconductors. The demonstrations shown by Tel Aviv University and Ithaca College NY are the perfect modern class room demonstrations, an important part of that class room appeal has to be the fact that they are attention grabbing and stunning to watch. Sit back and enjoy quantum mechanics in action. mechanics in action, click through to Channel Blipvert for all four video’s including the science behind the magic.
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Source: Quantum Levitation

Source: Matthew C. Sullivan

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