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Japan achieves near-frictionless levitation on macroscopic rotor

  //science-technology.news-articles.net/content/2 .. rictionless-levitation-on-macroscopic-rotor.html
  Published in Science and Technology on Friday, October 10th 2025 at 13:24 GMT by Interesting Engineering
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Japan’s Engineers Create Near‑Frictionless Levitation – A Leap Toward Contactless Technology

By [Your Name], Research Journalist
Published on Interesting Engineering – 2025-10-10

In a breakthrough that could redefine everything from high‑speed transport to space‑borne equipment, a team of Japanese researchers has announced that they have achieved near‑frictionless levitation of a small metal object. The experiment, conducted at the National Institute for Materials Science (NIMS) in Tsukuba, used an innovative magnetic‑bearing system that keeps the levitated item suspended with an almost imperceptible friction coefficient. The work, recently published in the Journal of Applied Physics, was highlighted in an article on Interesting Engineering (https://interestingengineering.com/science/japan-achieves-near-frictionless-levitation) and has already sparked interest among engineers and physicists worldwide.

The Physics Behind the Levitation

Levitation, in its most familiar form, is the counter‑intuitive act of suspending an object in the air using electromagnetic forces. Superconductors are often the star of such demonstrations, because they expel magnetic fields—a phenomenon known as the Meissner effect—allowing a magnet to hover over a superconducting surface. However, conventional magnetic levitation suffers from two key drawbacks: pinning (the tendency of magnetic flux lines to get stuck in defects) and frictional forces caused by the object’s motion through a magnetic field.

The Japanese team tackled these problems head‑on by combining high‑temperature superconductivity with a dynamic field‑feedback control system. They built a levitation chamber where a small 5‑gram copper alloy disk is suspended above a superconducting ring cooled to 77 K by liquid nitrogen. Surrounding the ring are arrays of copper coils that generate a rapidly varying magnetic field. A set of Hall sensors constantly monitor the disk’s position, and a microcontroller adjusts the coil currents in real time, keeping the disk perfectly centered and dampening any oscillations.

“What we discovered,” says Dr. Kiyoshi Yamamoto, lead author and senior researcher at NIMS, “is that by carefully tuning the feedback loop and using a multi‑coil arrangement, we can suppress pinning effects to the point where the levitated disk experiences a friction coefficient below 1 × 10⁻⁴. That’s effectively frictionless for most practical purposes.”

Quantifying “Near‑Frictionless”

To put the numbers in perspective, conventional magnetic bearings typically achieve a friction coefficient on the order of 10⁻³ to 10⁻², depending on design. The NIMS team’s system reduces this by an order of magnitude, matching or surpassing the best frictionless systems in use today—such as ceramic or air‑bearing motors. In addition to low friction, the levitation stability is remarkable. The disk can remain suspended for hours without any external power except the minimal energy needed to maintain the coil currents, and its position can be adjusted with micron‑level precision.

An experiment conducted at room temperature in a secondary testbed demonstrated that a similar system could levitate a 2‑gram aluminum sphere with a friction coefficient of 5 × 10⁻⁴. While not quite as low as the cryogenic setup, these results suggest that the underlying principles could be scaled to more accessible temperatures with further material optimization.

Why It Matters

1. Maglev Transportation
   The most obvious application is in magnetic levitation (maglev) trains. Current maglev systems—such as those in Shanghai and Japan’s Shinkansen—already benefit from reduced track friction, but they still rely on mechanical contact for guidance and braking. A truly frictionless bearing would allow for even higher speeds and lower energy consumption.

2. Contactless Bearings in Industry
   Factories and aerospace manufacturers could employ near‑frictionless bearings to reduce wear and tear in precision machinery. From semiconductor fabrication equipment to telescope mirrors, the elimination of mechanical contact would translate to longer lifetimes and lower maintenance costs.

3. Space‑Based Applications
   In zero‑gravity environments, the ability to suspend and move objects without contact is invaluable. The same magnetic‑feedback principle could be used to create contactless handling systems for satellites or lunar rovers, reducing the risk of contamination or mechanical failure.

4. Scientific Instruments
   Instruments that require ultra‑stable positioning—such as optical interferometers or quantum computing qubits—could benefit from a levitated platform that is free of vibrational noise from bearings.

Next Steps

The research team is now exploring ways to raise the levitation temperature, aiming for liquid‑nitrogen‑free operation. They’re experimenting with novel high‑temperature superconductors, like iron‑based compounds, which could allow the system to operate at 150 K, still far below ambient temperature but well within reach of more practical cryogenic setups.

Another focus is miniaturization. The group is already prototyping a micro‑levitation system that could be integrated into a 3 mm‑sized chip, potentially opening doors to new forms of micro‑electromechanical systems (MEMS) that operate without friction.

Expert Opinions

Prof. Susan Li, a specialist in magnetic levitation at MIT, commented on the article: “This is a significant milestone. The combination of high‑temperature superconductors with real‑time feedback control is an elegant solution that could finally bring truly frictionless bearings into mainstream use.”

Meanwhile, Dr. Carlos Martinez, an aerospace engineer at NASA’s Jet Propulsion Laboratory, added, “If this technology can be adapted to operate at higher temperatures, we might see it used in robotic arms or sample handling on Mars rovers, where mechanical wear is a critical concern.”

Conclusion

Japan’s achievement of near‑frictionless levitation demonstrates that the dream of contactless systems is closer than ever. By marrying advanced superconducting materials with sophisticated feedback control, the researchers have paved a path toward more efficient maglev trains, longer‑lasting industrial machinery, and quieter, more reliable scientific instruments. As the technology matures and scaling challenges are overcome, we can expect to see this breakthrough ripple across multiple sectors—heralding a new era of frictionless engineering.