Instead of relying on rigid molecular connections to hold nanoparticles in carefully planned arrangements, the team developed extremely flexible connectors that bend and adjust as particles come together. This unexpected strategy gives scientists a new way to control how nanoparticles organize themselves, allowing them to create crystal structures that have never been observed before.

The discovery could help overcome a major obstacle in materials science and open new possibilities for creating substances with precisely engineered properties. Potential applications include electronics, medicine, energy technologies, agriculture, and chemical manufacturing.

The findings, described in a paper that will appear in Nature Materials, demonstrate how the flexibility and electrical charges of molecular connectors can determine the structures that nanoparticles form.

MIT Researchers Challenge 20 Years of Materials Science

“People are interested in nanoparticle superlattices because of the promise of building designer materials where you have more say in what types of structures they can actually build into,” says Rob Macfarlane, the Richard P. Simmons (1953) Professor in Metallurgy in MIT’s Department of Materials Science and Engineering. “This is a new approach in nanoparticle assembly that hasn’t been investigated before. It’s exciting to have a new tool that is so counterintuitive. It’s the exact opposite of what the dogma has been for 20 years: that you need to make connector ligands rigid, and any deviation causes assembly to fail. We showed if you just crank it all the way to the opposite extreme, it works just as well.”

The research team also included MIT PhD candidate Nicholas Sbalbi, University of Delaware doctoral student Stephen Kronenberger, MIT undergraduate Hana Shinzawa, Matthew Ye PhD ’26, and Arthi Jayaraman, a former professor at the University of Delaware.

At the heart of the discovery is a basic principle of materials science: The way a material’s smallest components are arranged determines how that material behaves.

“That means if you know what your building blocks are and how they’re arranged, you can explain what properties materials have,” Macfarlane says. “Controlling that is how you make materials that have new properties.”

This principle is especially important when working with nanoparticles, which are extremely small pieces of matter whose shapes, sizes, and properties can be adjusted for different purposes. Scientists already use individual nanoparticles in technologies involving drug delivery, energy storage, computing, and sensors.

But turning these tiny building blocks into larger, organized materials presents a difficult challenge.

Why Nanoparticles Are So Difficult to Control

One of the biggest obstacles is controlling how nanoparticles attach to one another. Scientists need to determine not only how many neighboring particles each nanoparticle connects with, but also the directions in which those connections form.

Without that control, nanoparticles tend to assemble into tightly packed arrangements that restrict the variety of structures researchers can produce. This limits their ability to create materials with unusual or specialized properties.

Researchers have traditionally approached the problem in two ways. One strategy involves changing the shapes of nanoparticles to influence how they fit together. Another involves modifying specific areas of their surfaces so that only certain regions attract neighboring particles.

In effect, scientists attempt to control where the particles stick to one another, much like designing puzzle pieces that can connect only in particular positions.

Although these methods can produce useful structures, they are often complicated, highly specialized, and difficult to adapt for large-scale production.

“The challenge with both of those approaches is they’re difficult to do synthetically as we make the particles,” Macfarlane explains. “The methods for defining stickiness that have been developed are always bespoke: They work for one material, at one size scale, in one condition. It’s good for studying, but you can’t do much with it.”

Both strategies also depend on molecular connectors called ligands. These molecules attach to the surfaces of nanoparticles and help link neighboring particles together.

Traditionally, researchers have tried to make these ligands rigid so the connections remain at carefully controlled angles. This helps maintain a desired arrangement, but it also restricts the types of structures that can form and the functions they can perform.

The MIT team decided to explore a radically different possibility.

A Surprising Discovery About Flexible Molecular Bonds

Rather than forcing molecular connectors to remain in fixed positions, the researchers wondered whether giving them almost complete freedom to bend could offer an entirely new form of control.

“We thought, ‘Let’s do the exact opposite: make the bonds so flexible it doesn’t matter what direction they’re initially pointing.’ The ligands can then reorganize as the particles come together, and that reorganization itself limits how many neighbors each particle can bind,” Macfarlane says.

The idea reverses the usual approach to nanoparticle assembly. Instead of controlling the orientation of every connection in advance, the scientists allow the connectors to adjust naturally as the particles interact.

Macfarlane’s laboratory has spent years developing ways to construct different types of nanoparticles using attached polymer chains. Polymers are large molecules made of repeating smaller units, and their flexibility makes them useful for creating adjustable molecular connections.

For the new system, the team equipped nanoparticles with highly flexible ligands that carry electrical charges at their ends. Some have positive charges, while others have negative charges.

Because opposite electrical charges attract, the connector molecules naturally bend toward partners with the opposite charge. This attraction helps the nanoparticles join together, while the flexibility of the connectors influences how many connections each particle can make.

“The idea is, instead of defining a specific direction the bonds are going to occur in with complicated synthesis methods, we just said, ‘The bonds are going to be as flexible as they want to be, and they’ll spontaneously go to whatever valency is going to maximize bond stability,'” Macfarlane says.

In this context, valency refers to the number of connections a nanoparticle forms with its neighbors. By allowing the connectors to move freely, the researchers found that the system could naturally settle into stable arrangements without requiring every connection to be designed beforehand.

Scientists Create Crystal Structures Never Seen Before

Experiments led by Sbalbi demonstrated that the researchers could adjust the connections between nanoparticles by changing two relatively straightforward characteristics: the sizes of the particles and the lengths of their flexible molecular chains.

These adjustments altered how the particles assembled, giving the team control over the number of neighboring particles each one could connect with.

Most importantly, the researchers used this method to produce previously unseen crystal structures.

Crystals are materials whose building blocks form organized, repeating patterns. In this case, the repeating arrangements are made from nanoparticles rather than individual atoms or small molecules. Such ordered nanoparticle networks are often called superlattices.

By reducing the number of connections between neighboring particles, the team was able to create more open arrangements instead of the densely packed structures that commonly form during nanoparticle assembly.

“Without having to predesign where the particles connect or what their shapes are, we can control the number of bonds each particle has,” Macfarlane explains. “The amount of flexibility of the polymer dictates how many bonds it has. It allows us to lower the number of bonds each particle has and make lattices we have never seen before.”

The results suggest that molecular flexibility, once viewed as an obstacle to precise nanoparticle assembly, can instead become a powerful tool for engineering new material structures.

A New Path Toward Customizable Designer Materials

The researchers believe their method could bring scientists closer to a long-sought goal in materials science: choosing the properties of individual nanoparticles independently of the larger structures into which they assemble.

Ideally, scientists could select nanoparticles for their electrical, optical, chemical, or other useful characteristics and then organize those particles into whatever arrangement best serves a particular application.

In practice, however, existing assembly methods have made that level of flexibility difficult to achieve.

“We in the nanoparticle assembly community talk about having completely independent control over what your particle is and what assembly it goes into,” Macfarlane says. “In theory, that should be the case. In reality, it absolutely has not been.”

The new approach could help close that gap. Because the researchers can influence nanoparticle arrangements through the flexibility of their connectors and the attraction between electrical charges, they may be able to create a wider variety of structures without the complicated manufacturing techniques required by traditional methods.

The team also sees the discovery as a promising route toward producing customizable materials at larger scales, potentially helping move nanoparticle technologies beyond laboratory experiments and into practical use.

Potential Applications in Electronics, Medicine, and Energy

The ability to build more open and varied nanoparticle structures could prove particularly valuable for developing advanced materials.

In photonics, which involves controlling and manipulating light, precisely organized nanoparticles could help researchers engineer materials with specialized optical properties. In chemical catalysis, where substances accelerate chemical reactions, new particle arrangements could create opportunities to improve the way catalysts operate.

The approach may also support future developments in medicine, agriculture, electronics, and energy technologies.

A major advantage is that nanoparticles can already possess a wide range of desirable properties. By controlling how those particles come together, scientists may be able to combine their individual capabilities in new ways.

“Nanoparticle superlattices offer a way to create designer materials where your building blocks have all sort sorts of unique properties,” Macfarlane says. “But just densely packing these nanoparticles together limits your applications. This offers a way to get less dense formations of nanoparticles, and that’s where a lot of the interesting applications are.”

Although further development will be needed to translate the method into commercial technologies, the discovery establishes molecular flexibility as a new strategy for creating materials with tailored structures.

Instead of treating bending molecular connections as a problem to eliminate, scientists may now be able to use that flexibility to unlock arrangements that rigid designs could not easily achieve.

The research received partial support from the National Science Foundation, the Department of Energy, the U.S. Army, and the U.S. Navy.

On October 29, the agency issued a Request for Information seeking details about commercial technologies that could be used to service Hubble while it remains in orbit. The goal is to determine whether new spacecraft capabilities could keep the iconic observatory operating longer, improve its performance, or help bring its mission to a safe conclusion.

“Hubble still has important science ahead of it, and we should be looking at every reasonable opportunity to keep it delivering for as long as possible,” said NASA Administrator Jared Isaacman. “If there are innovative and cost-effective ways to extend the life of an asset already on orbit, we owe it to the American taxpayer and the scientific community to explore them. Extending Hubble’s life would mean more discoveries, more science, and more opportunities to expand our understanding of the universe.”

NASA Considers Raising Hubble Into a Higher Orbit

One possibility under consideration is sending a spacecraft to push Hubble into a higher orbit. This could counteract the gradual loss of altitude that threatens the telescope’s future and potentially allow it to continue making scientific discoveries for additional years.

NASA is also interested in missions that could service the telescope and improve its capabilities. Another option would focus on safely retiring Hubble when its scientific work is complete, either by guiding it through a controlled descent into Earth’s atmosphere or arranging for its disposal in orbit.

These possibilities are being explored rather than formally approved. By reaching out to commercial companies, NASA hopes to better understand what technologies are available and whether they could provide practical, affordable solutions.

“Hubble is a national icon that has fundamentally changed how humanity views our universe for more than 35 years,” said Nicky Fox, associate administrator, Science Mission Directorate, NASA Headquarters in Washington. “Commercial industry has rapidly evolved in recent years to offer new capabilities for in-space satellite capture and servicing. Given the time we have until Hubble’s anticipated re-entry, we are eager to explore the breadth of possibilities to boost Hubble to a higher orbit while we develop the flagship mission to follow.”

Companies interested in participating can review NASA’s Request for Information online. The agency is accepting responses until 3 p.m. EST on Monday, November 30.

Why Hubble Could Fall Back to Earth by 2034

Although Hubble continues to operate in space, its orbit is gradually shrinking. The telescope travels through low Earth orbit, where traces of Earth’s atmosphere create drag that slowly reduces the altitude of orbiting spacecraft.

Even hundreds of miles above the planet, the atmosphere is not completely absent. The tiny amount of remaining gas produces resistance as spacecraft move through it. Over long periods, this effect can cause satellites to lose altitude and eventually descend into denser layers of the atmosphere.

Unlike spacecraft equipped with engines that can periodically raise their orbits, Hubble has no propulsion system capable of maintaining its altitude. Without outside assistance, it cannot reverse this gradual orbital decline.

NASA’s current analysis suggests that Hubble will likely reenter Earth’s atmosphere sometime between 2033 and 2034. To prevent that outcome through an orbital boost, the agency expects that a mission would need to occur by 2032.

That timeline leaves a limited window to evaluate potential solutions, develop a mission, and carry it out before the telescope descends too far.

Extending Hubble’s Legacy of Cosmic Discoveries

Since beginning operations more than three decades ago, Hubble has become one of the most influential scientific observatories ever launched. Its observations have helped reshape astronomers’ understanding of the cosmos, and the telescope continues to produce discoveries that advance research across many areas of astronomy.

Hubble is also the product of a longstanding international partnership between NASA and ESA (European Space Agency).

NASA’s Goddard Space Flight Center in Greenbelt, Maryland, oversees the telescope and its mission operations, with additional operational support from Denver-based Lockheed Martin Space.

Scientific operations are handled by the Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy on NASA’s behalf.

With commercial spaceflight technology advancing, NASA is now evaluating whether Hubble could benefit from capabilities that were not available when it was originally designed. A successful mission to raise its orbit or enhance its systems could allow the historic telescope to continue exploring the universe well beyond its currently projected orbital lifetime.

The breakthrough comes from a research team led by the U.S. Department of Energy’s SLAC National Accelerator Laboratory. In a study published in Science, the researchers presented compelling experimental evidence for altermagnetism, a distinct magnetic phase that combines important characteristics of the two traditionally recognized types.

“In the past few years, scientists have observed phenomena that don’t fit neatly into the ferromagnetism-antiferromagnetism dichotomy,” explained lead author Daniel Jost, associate scientist at SLAC and Stanford Institute for Materials and Energy Sciences. “Researchers have been compiling evidence of a third type of magnetism that bridges the qualities of these two classes. We believe our results provide robust experimental confirmation that this third phase — altermagnetism — is real.”

The team focused on manganese telluride (MnTe), a material that had long been classified as an antiferromagnet. Building on earlier research, the scientists identified direct evidence of chirality, a distinctive asymmetry in the material’s magnetic structure. This property resembles the way a spiral staircase or screw twists in a particular direction and provides a crucial signature of altermagnetism.

Beyond its importance for fundamental physics, the finding could help researchers develop magnetic materials with properties suited to future technologies, including advanced memory systems, quantum devices, and more energy-efficient data centers.

Understanding the Two Traditional Types of Magnetism

Magnetism is familiar from everyday experiences, whether it is a refrigerator magnet holding up a photograph or a compass aligning with Earth’s magnetic field. But the physics behind these effects is far more complicated than it appears.

At the atomic level, magnetism is connected to a quantum property of electrons known as spin. Although spin is not literally an electron rotating like a tiny ball, it behaves in certain ways as though the electron has its own angular momentum. Scientists commonly describe the two possible spin orientations as “up” and “down.”

When these spins become organized into particular patterns, a material can exhibit magnetic properties. However, that does not necessarily mean it will produce an externally detectable magnetic field.

In ferromagnetic materials, electron spins align in the same direction (up-up-up or down-down-down). Their combined effect produces the familiar magnetic field associated with ordinary magnets. People have used materials with this behavior for thousands of years.

A second category, identified in 1933, works differently. In antiferromagnets, neighboring electron spins point in opposite directions (up-down-up-down). Because the magnetic contributions oppose one another, they cancel out, leaving no overall magnetization.

A Third Type of Magnetism Challenges the Old Rules

For almost nine decades, these two categories provided the basic framework for understanding how magnetic order arises in materials. However, experimental observations in recent years began revealing behavior that neither category could fully explain.

Some materials displayed alternating electron spins and no overall magnetization, just like antiferromagnets. Yet they could also support useful spin currents, a property associated with ferromagnetic behavior. Spin currents allow information to be carried through the spin properties of electrons rather than relying entirely on their electrical charge.

The unusual combination suggested that scientists were dealing with something fundamentally different. In 2022, researchers introduced the term “altermagnets” for materials belonging to this proposed third magnetic class.

The key difference lies in the arrangement of atoms within the material. Altermagnets have alternating spin orientations (up-down-up-down), but the crystal structures surrounding the oppositely aligned spins are rotated relative to one another.

This rotation breaks a form of symmetry that exists in conventional antiferromagnets. Although the distinction is subtle, it can dramatically change how electrons behave, allowing altermagnets to combine properties once considered incompatible.

Scientists Find the Missing Evidence for Altermagnetism

Even as experimental support for altermagnetism accumulated, researchers still needed a decisive way to establish that it represented a genuinely distinct magnetic phase.

“By 2024, there were some factors that spoke strongly in favor of altermagnetism being real,” Jost said, “but there was still a missing piece to the puzzle.”

That missing evidence involved chirality, a property sometimes described as “handedness.” An object is chiral when its mirror image cannot be perfectly aligned with the original. Human hands provide a simple example: Your left and right hands are mirror images, but a left hand cannot fit properly into a right-handed glove.

In an altermagnet, the unusual arrangement of atoms and electron spins can create this kind of handedness in the material’s electronic and magnetic structure. Conventional antiferromagnets do not exhibit the same characteristic chiral signature.

Detecting that difference would provide a powerful way to distinguish a true altermagnet from a material that merely resembles one.

The researchers selected manganese telluride as their test material. For decades, scientists considered it an ordinary antiferromagnet, but more recent studies had raised the possibility that it belonged to the newly proposed category.

Powerful X-Rays Reveal a Hidden Magnetic Signature

To investigate the material’s unusual properties, the team conducted experiments at the European Synchrotron Radiation Facility (ESRF) in France. The facility’s ID32 beamline produces precisely controlled polarized X-rays, allowing scientists to examine subtle magnetic structures that are otherwise extremely difficult to detect.

The researchers used circularly polarized X-rays, which have electric fields that rotate in either a left-handed or right-handed direction as the light travels. By measuring how the material scattered these two forms of light, they could search for evidence of chirality.

“Chiral materials scatter left-handed polarized X-ray beams differently than they do right-handed beams,” explained Jost. “Non-chiral materials would scatter each beam of light the same way.”

The experiment revealed a clear difference in the way manganese telluride interacted with the two X-ray polarizations. This distinctive chiral response was precisely the kind of signal expected from altermagnetism and would not be present in a conventional antiferromagnet.

“This chiral signature gave us the solid experimental ground to say altermagnetism stands in a class of its own,” Jost said.

The researchers first performed the experiment in 2024. They returned in early 2025 and repeated the measurements, successfully reproducing the results and strengthening the evidence for the new magnetic phase.

“This technique helped us confirm that manganese telluride was really exhibiting altermagnetic properties,” said Rachel Nickel, postdoctoral scientist with ESRF, a co-author who helped design and conduct the experiment on the ID32 beamline. “Altermagnetism was only proposed a few years ago, and the rapid progress in confirming these models is incredible.”

Why Altermagnetism Could Transform Future Computers

The discovery could have important consequences for spintronics, a growing field that seeks to use electron spin to develop more capable electronic devices.

Conventional electronics store and process information primarily by controlling the electrical charge of electrons. Spintronics adds another way to work with information by taking advantage of electron spin as well.

This extra capability could enable devices that operate faster, withstand interference more effectively, and consume substantially less electricity. Such improvements would be especially valuable in computer memory, large data centers, and other technologies that require enormous amounts of information processing.

However, the two traditional types of magnetism present different obstacles that have limited the development of spintronic systems.

“Ferromagnets are too easily influenced by magnetic fields,” Jost explained. “If you have a permanent magnet in your pocket and walk by a spintronic device built with ferromagnets, you could start flipping the bits, scrambling the information stored there. Antiferromagnets fix that problem, but they are practically invisible — so you can’t easily read the data stored in them or use them to drive efficient spin currents.”

Altermagnets offer a potentially valuable alternative. Like antiferromagnets, their opposing spins produce no overall magnetization, helping protect them against unwanted magnetic interference. At the same time, their unusual electronic structure allows them to generate spin-polarized currents that can be used to retrieve information.

“Altermagnets combine the best of both,” Jost said. “They have zero net magnetization, so they’re stable, but they still have the capability to generate spin-polarized currents needed to easily extract information. That gives you an additional degree of freedom to work with.”

A New Frontier for Quantum Technology and Electronics

Confirming altermagnetism gives scientists a new class of materials to investigate and potentially engineer for technological applications. By combining magnetic stability with the ability to manipulate spin-based information, these materials could help overcome challenges that have held back conventional spintronic devices.

The next step will be learning how to control altermagnetic states using external influences such as light and electricity. Researchers hope that mastering this control will make it possible to design practical devices that take advantage of the unusual magnetic properties.

Although significant development is still needed before these materials can be widely used, the findings establish a stronger experimental foundation for future work on quantum technologies, computer memory, and more efficient data centers.

The research received partial funding from the DOE Office of Science.