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Scientist Built the World’s Most Powerful Resistive Magnet. It Could Change the Future of Superconducting.

Clocking in 42.02 Tesla, this magnet will hopefully power future discoveries in the field of material science.

  • On September 22, the Chinese Academy of Sciences’ Steady High Magnetic Field Laboratory (CHMFL) sustained the strongest magnetic field using a resistive magnet, at 42.02 tesla.
  • This surpasses the previous record, which was set by the U.S. National High Magnetic Laboratory back in 2017.
  • Open to international collaborators, this high magnetic field will hopefully help scientists make innovations in material science—particularly in the realm of superconductors.

#magnet #technology #superconducting #newsonleo

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The Quest for Magnetic Supremacy: A Breakthrough in High Magnetic Fields

The pursuit of scientific excellence has led to numerous groundbreaking discoveries throughout history. One such area where scientists have been pushing the boundaries of what's thought possible is the realm of high magnetic fields. On September 22, the Chinese Academy of Sciences' Steady High Magnetic Field Laboratory (CHMFL) achieved a major milestone by sustaining a magnetic field of 42.02 Tesla using a resistive magnet, surpassing the previous record of 41.4 tesla set by the U.S. National High Magnetic Laboratory in 2017.

This achievement is significant not only because it demonstrates the laboratory's expertise in creating high magnetic fields but also because it highlights the potential of hybrid magnets to create even more powerful fields than their individual components. In 2022, CHMFL created a hybrid magnet that produced an astonishing 45.22 tesla, a combination of resistive and superconducting technologies.

So, what's the significance of high magnetic fields? For starters, they have far-reaching implications for material science, particularly in the realm of superconductors. High magnetic fields have also played a crucial role in numerous Nobel Prize-winning discoveries. By pushing the boundaries of what's possible, scientists can unlock new secrets about the behavior of materials and the fundamental laws of physics.

CHMFL's achievement is not just about beating a record; it's also about collaboration and international cooperation. The laboratory has made its magnets available for international research, paving the way for new discoveries and breakthroughs. In fact, the power of high magnetic fields has already led to numerous groundbreaking findings, from the discovery of new superconductors to a deeper understanding of the behavior of materials under extreme conditions.

As scientists continue to push the limits of what's possible, they're getting closer to the upper bounds of magnetic fields. Astronomers have already detected 24 magnetars, neutron stars with incredibly powerful magnetic fields, and more are awaiting official confirmation. In 2022, a team of scientists using China's Insight-HXMT X-ray telescope discovered the strongest magnetic field ever recorded, a staggering 1.6 billion tesla – roughly a million billion times stronger than Earth's magnetic field.

The pursuit of magnetic supremacy is not just about setting records; it's about unlocking the secrets of the universe. Who knows what wonders await us as we delve deeper into the world of high magnetic fields? Perhaps it's time to start thinking about a Guinness book of Universe Records.

A Superconductor Found in Nature Has Rocked the Scientific World

The quest for boundless energy takes an electrifying turn with this magic mineral.

  • Scientists have identified the first unconventional superconductor that you can find in nature.
  • Conventional superconductors follow a specific, well known paradigm called BCS.
  • Miassite does occur naturally, but this test was on a pure, lab-made sample.

#superconductor #science #technology

In new research, scientists explain how one mineral found in nature is more than just a typical superconductor. Miassite is a gray, metallic mineral made of rhodium and sulfur and, as Science Alert explains, was identified as a regular superconductor in 2010. But now, miassite has passed a variety of odd-seeming tests that show it’s also an “unconventional” superconductor—joining a small group that, so far, has only included laboratory-conceived materials. That research appears now in the journal Communications Materials, and to understand what it all means, we first need to understand the conventional superconductors.

Inside a regular material that conducts electricity, moving electrons pass through where they have room to do so. But those paths are not huge or perfect, so the electrons experience resistance. Conductors are often organized by how much resistance they produce—the less resistance is better. Some products, like heating pads, intentionally use resistance because the electrons deposit more of their energy into the structure when they get “stuck.”

Unconventional Superconductivity: The Groundbreaking Discovery of Miassite, a Natural Mineral with Unique Properties

In a groundbreaking study published in the journal Communications Materials, scientists have made a remarkable discovery that challenges our understanding of superconductivity. Miassite, a gray, metallic mineral composed of rhodium and sulfur, has been found to exhibit unconventional superconductivity, a property previously thought to be exclusive to laboratory-conceived materials. This discovery has significant implications for our understanding of the fundamental nature of superconductivity and its potential applications.

What is Superconductivity?

Superconductivity is a phenomenon where electrical resistance inside a solid material drops to zero. This occurs when the material is cooled to extremely low temperatures, typically near absolute zero. The major theory that explains superconductors, known as the Bardeen-Cooper-Schrieffer Theory (BCS), relies on special electron pairs held at low temperatures in the state of matter called Bose-Einstein Condensate (BEC). According to BCS theory, superconductors require a specific arrangement of electrons and phonons (quantized sound waves) to achieve zero resistance.

Conventional vs. Unconventional Superconductors

Conventional superconductors, such as those made of niobium or aluminum, only achieve superconductivity at extremely low temperatures and under high pressure. Unconventional superconductors, on the other hand, do not conform to BCS theory and exhibit superconductivity at higher temperatures. These materials are typically synthesized in a laboratory and require complex processing techniques. The discovery of miassite's unconventional superconductivity is significant because it suggests that nature has created a material that defies the conventional understanding of superconductivity.

The Discovery of Miassite

Miassite, a naturally occurring mineral, was first identified as a regular superconductor in 2010. However, recent research has revealed that it also exhibits unconventional superconductivity, making it the first naturally occurring mineral to demonstrate this property. The researchers used a combination of techniques, including X-ray diffraction, electron microscopy, and spectroscopy, to study the crystal structure and electronic properties of miassite.

Testing Miassite

To establish miassite's unconventional superconductivity, researchers conducted three different tests:

  1. The London penetration depth test, which measures the reaction of the material to a weak magnetic field. This test revealed that miassite exhibits a unique magnetic response that is not typical of conventional superconductors.
  2. Creating defects in the material, which can affect the temperature at which it becomes a superconductor. This test showed that miassite's superconducting properties are robust and can withstand defects.
  3. Studying the nature and quantity of energy gaps in the material, which enables superconductivity. This test revealed that miassite has a unique energy gap structure that is not consistent with BCS theory.

Implications and Future Research

The discovery of miassite's unconventional superconductivity opens up new avenues for research and potential applications. As a naturally occurring mineral, miassite is more accessible and easier to study than laboratory-conceived materials. This could lead to a better understanding of the underlying mechanisms of superconductivity and potentially pave the way for the development of new materials with unique properties. Future research could focus on understanding the crystal structure and electronic properties of miassite, as well as exploring its potential applications in fields such as energy storage and transmission.

Conclusion

The discovery of miassite's unconventional superconductivity is a significant breakthrough that challenges our understanding of this phenomenon. As researchers continue to study this natural mineral, we may uncover new insights into the fundamental nature of superconductivity and its potential applications. This discovery has the potential to revolutionize our understanding of superconductivity and could lead to the development of new materials and technologies with unprecedented properties.

Room-Temperature Superconductors: Why Scientists Are Still Searching for This ‘Holy Grail’

Improving the technology of superconductors, already used in the Large Hadron Collider and MRI machines, would revolutionize our everyday life. Here’s how.

#superconductors #technology #science

Electricity powers the modern world—unfortunately, it’s pretty inefficient.

Some 700,000 circuit miles of transmission lines and another 5.5 million miles of distribution lines make up the U.S. electric grid, but those aluminum and copper wires, while being extremely good conductors, are far from perfect. Because electric current meets some small measure of resistance while traveling through those wires, lots of energy is lost as heat. According to the National Defense Research Council, five percent of the energy produced in the U.S. is completely wasted during this electrical journey. While that may seem like a small slice of the electron pie, that’s enough juice to power all of central America four times over.

But the electric grid is only one (albeit big) example of wasted energy—anything that requires electricity to function similarly wastes energy in this way. And according to physics, that’s just the way it has to be. Or is it?

Turns out, a very peculiar thing happens when metals, alloys, and other materials get cold, like approaching absolute zero cold: electrical resistance disappears. Science defines these as superconductors, a large family of diverse materials that underpin some of the most advanced technologies in the world.

“This is the promise of superconductors,” Nadya Mason, a condensed matter physicist at the University of Illinois Urbana-Champaign, tells Popular Mechanics. “Superconductors are the materials where electrons can move through the material without losing energy as heat … but the problem with superconductors so far is that they only work at extremely low temperatures.”

Because of these bone-shattering temperatures, superconductors are mostly relegated to advanced technologies. But what if science could somehow find a material that performed this atomic superconducting dance at room temperature?

“Any metal in principle can be a superconductor … [but] people are interested in finding new materials where the transition temperature, where the material goes superconducting, is higher and higher,” Richard Greene, a condensed matter physicist and founding director of the Center for Superconductivity Research at the University of Maryland, tells Popular Mechanics. “There’s always been the hope of making a room-temperature superconductor, it’s sort of a holy grail.”

And like a modern-day Sir Galahad, researchers from South Korea believe that search is over, publishing two papers in July 2023 detailing a new material that’s supposedly a superconductor at room temperature and ambient pressure. But despite the viral sensation of this so-called “discovery,” experts in the field aren’t so certain, and efforts to replicate LK-99, the supposed room-temperature superconductor, have failed.

To fully understand this scientific drama, let’s talk about superconductors: their history, their structure, and their incredible potential.

Mercury Practically Zero”

Humans have known about electricity for thousands of years, but it wasn’t until the turn of the 20th century when scientists finally discovered one of its most puzzling attributes. This millennia-long delay, in part, was because humans had no way of simulating temperatures approaching absolute zero, or -459.67 degrees Fahrenheit.

That changed on April 8, 1911, when Dutch physicist Heike Kamerlingh Onnes, while experimenting with liquid helium, plunged the metal Mercury all the way down to just 3 Kelvin. With his assistant soon shouting “zero, zero, still zero!” from a nearby room, Kamerlingh Onnes jotted in his notebook, “mercury practically zero,” a reference to the metal’s complete lack of electrical resistance.

He didn’t know it at the time, but the Dutch scientist had just discovered an entirely new field of physics, a feat that would earn him the Nobel Prize in 1913. It’s from this moment that the era of superconductors truly began.

“[Superconductivity] is an amazing phenomenon, and it took about 50 years before they figured out how it works,” Greene says. “You actually need to understand quantum mechanics—you can’t understand it using classical physics.”

That leap in understanding arrived in 1957, when three physicists from the University of Illinois—John Bardeen, Leon Neil Cooper, and John Robert Schrieffe—developed the BCS theory (named after their last initials) to describe all the quantum goings-on when a metal becomes a superconductor at critical temperature, or Tc (which varies by material).

The theory goes that negatively charged electrons, which would usually repel each other under normal circumstances, actually form pairs (known as “cooper pairs”) when cooled down to Tc. This pairing is effectively created by electron interactions with vibrations, or “phonons,” in the atomic crystalline structure. The result? Zero electrical resistance.

“These electrons pair up over distances that are larger than the scale at which they’d be hitting atoms,” Mason says. “So if you imagine a road that has a lot of bumps in it, [electron pairs] lift themselves up above the road … so that the bumps are irrelevant to them.”

Superconductors also have unique magnetic properties, as they naturally expel magnetic fields while simultaneously creating eddy currents of their own. This is what’s known as the “Meissner effect,” and it explains why levitation is often regarded as an effect of superconductivity (though it can be caused by other means).

In 1933, German physicists Walther Meißner (anglicized “Meissner”) and Robert Ochsenfeld discovered a strange habit of superconductors. When materials were cooled to their transition temperature, they expelled magnetic fields. This was true when a substance was cooled in the presence of magnetic fields or applied after the fact.

“If you try to change the magnetic field through a metal, a current will be induced in that metal and will try to oppose the change in that magnetic field,” Greene says. “When the material goes superconducting and the magnetic field is expelled, that’s a change in the magnetic field. Normally, that current would die out because the metal has resistance … but if you have a superconductor, then there’s no resistance anymore, so the current stays there forever.”
This induced diamagnetism—magnetic field repulsion—is why levitation is a tell-tale sign of a superconductor, but if you induce a strong enough magnetic field (a specific threshold known as “critical field”), the material will stop being superconductive. However, it’s worth noting that other effects can also cause levitation (which is why you can buy a variety of levitating desk toys on Amazon).

Although you can induce superconductivity by changing the atomic structure with increased pressure, the big secret to this electron magic trick is temperature. Because temperature is essentially just energy by another name, it brings with it thermal excitations that disrupt these paired electrons, Mason says. So for a material to be a superconductor, that thermal energy must be lower than the paired electrons’ energy. That’s why superconductors usually occur at temperatures approaching absolute zero, when such thermal energy is extremely low.

Emphasis on the word “usually.”

Things Start Warming Up

So far, this has all been a standard description of superconductors—the kind of stuff that had Kamerlingh Onnes scratching his head back in 1911. But the term “superconductor” is really an umbrella term for a variety of materials that can achieve superconductivity in a variety of ways.

Some materials—known as s-wave, d-wave, p-wave, and recently g-wave superconductors—are categorized by how two electrons specifically pair up in the first place. Other superconductors use entirely different mechanisms that don’t require phonons at all, or react to magnetic fields in different ways (Type I and Type II superconductors), and some even reach Tc at temperatures scientists once thought impossible.

“Based on the [BCS] theory, it was thought that nothing could superconduct above 40 Kelvin,” Greene says. “That idea was completely destroyed in the 1980s when a new material was discovered: copper oxides.”

As you increase the temperature or strength of the magnetic field applied to a superconducting material, at some point that superconductivity will break down—and therein lies the the main difference between Type I and Type II superconductors. Type I superconductors, usually metals or metalloids, lose their superconducting properties and return to a “normal” state at a specific critical field level (Hc). Type II superconductors, often alloys or complex oxide ceramics, exhibit a sort of buffer phase (or mixed state), in which there are two critical field thresholds.

When the first one (Hc1) is reached, magnetic field lines begin penetrating the material though it still retains superconductivity—that is, until it reaches its second threshold (Hc2). This second critical field boundary is usually much higher than Hc found in Type I superconductors, which is why Type II superconductors are preferable in many engineering applications.

For instance, Type II superconductors like niobium titanium (NbTi) are used to create high-field superconducting magnets for various types of fusion reactors. The ITER tokamak based in Saint-Paul-lez-Durance, France, uses NbTi in its poloidal field coils, which are essential in plasma confinement. Meanwhile, the Wendelstein 7-X stellarator in Greifswald, Germany, uses NbTi for its magnets.

These new materials, such as the ceramic known as yttrium barium copper oxide, became a superconductor at 93 Kelvin—still cold, but not absolute-zero cold. But maybe even more importantly, these materials were the first superconductors above the boiling point of liquid nitrogen, which is cheaper and easier to handle than liquid helium. Today, the highest-temperature superconductor under ambient pressure is around 130 Kelvin, or -225 degrees Fahrenheit.

Even at these low temperatures and high pressures, superconductors have found their way into a variety of world-changing technologies, mostly through superconducting wires that create powerful electromagnets. CERN’s Large Hadron Collider, the largest particle accelerator in the world, uses superconducting electromagnets to “bend and tighten” a particle’s trajectory; and the ITER tokamak, the most advanced fusion reactor on the planet, will contain the most integrated superconducting magnet system ever built when it goes online in 2025. But the most ubiquitous use of superconductors is in magnetic resonance imaging (MRI) machines, which leverage superconducting electromagnets to glimpse the human body in unprecedented detail.

While these inventions are certainly miraculous, they are still cumbersome as these materials constantly require ultra-cool temperatures (usually in the form of expensive liquid helium)—not exactly something that can feasibly cover the millions of miles of cable that make up the U.S. electric grid.

But if science could somehow discover a material that acts at a superconductor at room temperature, our electric world would enter an entirely new era.

New Era or False Start?
The history of electricity is punctuated with many major moments. Michael Faraday’s discovery of electromagnetic induction, James Clerk Maxwell’s famous equations, Nikola Tesla’s creation of an A/C induction motor, and Bell Labs’ invention of the transistor have all earned a top spot—and the discovery of a room-temperature superconductor would surely be their equal.

“Even though the mechanism may not be known and even though people are still trying to understand high-temperature superconductors, there’s no physics reason why we can’t have a room-temperature superconductor,” Mason says. “The application possibilities would broaden tremendously if we had [one].”

It’s this immense promise (and likely a guaranteed Nobel Prize) that’s caused some furor in condensed-matter physics in recent years. Paper after paper claims to have found this elusive, superconducting White Whale, only for those hopes to be dashed along the rocky shores of reality.

Claims of room-temperature superconductivity date back to at least the year 2000, though many of them require immensely high pressures. A high-profile dud in recent memory came in October 2020, when a physicist from the University of Rochester in New York published a paper in the journal Nature announcing the discovery of a superconducting material at 59 degrees Fahrenheit (albeit under extreme pressure). The work captured tons of headlines, but Nature retracted the paper two years later after physicists failed to reproduce the results, citing “data-processing irregularities.”

But the newest—and most perplexing—candidate comes from a team of South Korean researchers, who in two separate papers detail the properties of a material they call “LK-99”, a lab-made material containing lead, oxygen, phosphorus, and sulfur. According to the paper, LK-99 showcases tell-tale signs of the Meissner effect (it levitates) and it is supposedly a superconductor with a Tc of 260 degrees Fahrenheit at ambient pressure, meaning it can basically operate in any environment on Earth.

This non-peer-reviewed preprint, boldly titled “The First Room-Temperature Ambient-Pressure Superconductor,” ignited a firestorm last month—both online and in physics departments around the world—as experts and laboratories rushed to recreate the material and reproduce these amazing results. But even from the very beginning, most condensed-matter physicists, including Mason and Greene, were skeptical.

“Even though they’ve shown levitation and resistance versus temperature curves in their paper … none of those measurements seem to have the reliability that a typical paper reporting superconductivity would have,” Greene says. “For example, one of the papers shows electrical resistance versus temperature, and when it comes to superconductivity there’s a very sharp drop in the resistance … the drop is much too sharp. It wouldn’t happen that quickly.”

Greene and Mason also mention some graph inconsistencies that make it hard to discern if this material is even a superconductor at all.

“I think one thing that’s exciting about this paper is that they were very clear about how they made the material. It’s a material that many people can make and reproduce,” Mason says, but he also points out a few red flags. “The resistivity plot is troublesome to me … if you took their plot of a superconductor, and just put gold on the same plot, gold would look like there was also zero resistance.”

At first, for every validation study that showed promising results, another study took the wind out of Ahab’s metaphorical sails. Finally, two weeks after its arrival, the International Center for Quantum Materials—an influential Chinese superconductor lab—confirmed that LK-99 wasn’t a superconductor at all, but instead displayed a kind of ferromagnetism.

So for now, the dream of room-temperature superconductors is on pause. But despite LK-99’s unfortunate fate, the dream has never been so tantalizing.