Physicists Search for Levitation and Perfect Efficiency

Physicists Search for Levitation and Perfect Efficiency

Date Published: April 10, 2019
Zachary Savitsky

Kelley rides to work every morning on a train that floats above its tracks.

Passing by, she records a video of children at the local hover board park on her cell phone, which she hasn’t had to charge in months. She then departs the train and takes the elevator up to floor 112 in a matter of seconds.

Kelley lives in a not-so-distant world powered by more effective electric and magnetic fields. She lives in a world of superconductors.

What’s holding us back from this fantastic future is the fact that superconductivity, responsible for the properties behind these advancements, typically only exists in materials at very low temperatures (around -250 degrees Celsius). Dr. James Hamlin and his research team at the University of Florida are searching for a metal that exhibits these characteristics at room temperature – a discovery that would help the world become more like Kelley’s.

To understand these special properties, it is essential first to look at the categorization of materials based on conductivity, or how easily electrons move through them. Conductors have a relatively low electrical resistance, meaning they conduct electricity well, while insulators have a higher electrical resistance and lower conductivity.

A third category of materials, known as superconductors, have zero electrical resistance and therefore conduct electricity with perfect efficiency without any energy loss. Superconductors also have another unique characteristic: They exhibit something called the Meissner Effect, which implies that they directly repel any magnetic field they encounter – allowing them to levitate above magnets.

The potential implications of these properties are plentiful. Without energy loss, electricity and information could be transferred faster, cheaper and on a much larger scale.

Additionally, the diamagnetic properties of superconductors provide an opportunity to remove all friction and avoid obstacles by suspending themselves in air. Superconducting trains hover above their tracks, accelerating without any resistance from the ground.

The problem is that these properties only occur when the metals are cooled to a certain very low temperature, known as the critical temperature (Tc). Historically, cooling metals down to their very low critical temperatures has been too expensive to justify using them in everyday life.

“The whole goal of our research is to raise that critical temperature to room temperature,” Hamlin said.

Hamlin’s lab tests hundreds of chemical compounds for their critical temperatures in the hopes of finding one that exhibits superconducting properties at an unusually high temperature. To speed up this process, though, he and his team apply pressure to the metals to turn one material into another very rapidly.

In the wake of new advancements like the equipment in Hamlin’s lab, researchers have made significant progress lately to discover room-temperature superconductors.

Just a few years ago, a research group discovered and confirmed the highest known Tc. In the past few months, multiple results with high-pressure critical temperatures above -58 degrees Celsius have emerged, edging that critical mark much closer to room temperature.

While these reports are dealing with metals under conditions much more intense than atmospheric pressure, the results are nothing shy of groundbreaking. The process resembles the formation of diamonds by squeezing coal; while it’s not exactly feasible for mass production, it establishes the fundamental concepts that lay the groundwork.

“I think the odds are good for the simple reason that we don’t know any fundamental reason why the critical temperature of a superconductor can’t be at room temperature,” said Peter Hirschfeld, a theoretical physicist at UF specializing in superconductors.

We still have some ways to go until the current technology catches up with Kelley’s utopia, but it may not be as far off as it seems.