Conceptual image of quantum computing magnetometer. (ยฉ RoAlin - stock.adobe.com)
Voltage-controlled ‘vortions’ unlock new era of energy-efficient memory
In a nutshell
- Scientists have created “vortions” — tiny swirling magnetic structures controlled by voltage rather than electric current — making computer memory potentially much more energy-efficient
- Unlike traditional magnetic memory, vortions can be adjusted to various states after creation, mimicking the analog way human brain synapses work rather than just binary on/off states
- This breakthrough could lead to computers that process information more like human brains while consuming significantly less power, potentially revolutionizing artificial intelligence and data storage
BARCELONA — Computers are hungry beasts. They devour vast amounts of power, especially when writing data to memoryโa process that traditionally uses electric currents and generates wasteful heat. But what if we could control magnetic information storage with voltage instead? This approach is gaining traction as researchers seek more energy-efficient computing solutions for our data-hungry world.
In a paper published in Nature Communications, researchers from The Autonomous University of Barcelona have unveiled a novel nanoscale magnetic state they’ve dubbed a “vortion” (short for magneto-ionic vortex). This innovative approach uses voltage-controlled ion movement to create and manipulate swirling magnetic patterns at the nanoscale, potentially transforming how computers store and process information.
“This is a so far unexplored object at the nanoscale,” explains Jordi Sort, an ICREA researcher in the UAB Department of Physics and director of the research, in a statement. “There is a great demand for controlling magnetic states at the nanoscale but, surprisingly, most of the research in magneto-ionics has so far focused on the study of films of continuous materials. If we look at the effects of ion displacement in discrete structures of nanometer dimensions, the ‘nanodots’ we have analyzed, we see that very interesting dynamically evolving spin configurations appear, which are unique to these types of structures.”
The research team, led by scientists from Universitat Autรฒnoma de Barcelona, has discovered a way to precisely control the magnetic properties of tiny dots of metal with extremely low power consumption. Their method allows for continuous, analog adjustment of magnetizationโsimilar to turning a dimmer switch rather than flipping a binary on/off toggleโopening exciting possibilities for brain-inspired computing technologies.
How Vortions Work
At the heart of this innovation is a clever manipulation of nitrogen ions within specially engineered iron-cobalt-nitrogen (FeCoN) nanomagnets. By applying voltage, researchers can extract nitrogen ions from these tiny dots, transforming them from magnetically inert to magnetically active in controlled, gradual ways. This creates distinctive swirling magnetic patternsโvortices that can be precisely tuned and manipulated.
“With the ‘vortions’ we developed, we can have unprecedented control of magnetic properties such as magnetization, coercivity, remanence, anisotropy or the critical fields at which vortions are formed or annihilated. These are fundamental properties for storing information in magnetic memories, which we are now able to control and tune in an analog and reversible manner by a voltage-activated process with very low energy consumption,” explains Irena Spasojeviฤ, postdoctoral researcher in the UAB Department of Physics and first author of the paper.
Unlike traditional magnetic vortices, which are typically fixed in their properties once manufactured, these voltage-controlled vortions offer unprecedented flexibility. Their magnetic strength, stability, and behavior can all be adjusted after fabrication, eliminating the need for energy-intensive techniques like laser pulses or electrical currents to manipulate magnetic states.
“The voltage actuation procedure, instead of using electric current, prevents heating in devices such as laptops, servers and data centers, and it drastically reduces energy loss,” Spasojeviฤ adds.
The Brain-Computer Connection
Traditional computing relies on binary statesโones and zerosโbut the human brain processes information in a much more nuanced, analog fashion with varying connection strengths between neurons. This new technology moves closer to brain-like computing by enabling analog states with continuous degrees of magnetization that can be adjusted with voltage, potentially leading to more efficient and sophisticated computing architectures.
By controlling how long voltage is applied, researchers can precisely adjust the thickness of the ferromagnetic layer, enabling transitions between different magnetic statesโfrom nonmagnetic to single-domain to vortex states.
Researchers have shown that by precisely controlling the thickness of the voltage-generated magnetic layer, the magnetic state of the material can be varied at will, in a controlled and reversible manner, between a non-magnetic state, a state with a uniform magnetic orientation (such as that found in a magnet), and the new magneto-ionic vortex state.
From Lab to Applications
“We envision, for example, the integration of reconfigurable magneto-ionic vortices in neural networks as dynamic synapses, capable of mimicking the behavior of biological synapses,” Sort explains.
In the brain, the connections between neurons, the synapses, have different weights (intensities) that adapt dynamically according to the activity and learning process. Similarly, “vortions” could provide tuneable neuronal synaptic weights, reflected in reconfigurable magnetization or anisotropy values, for brain-inspired spintronic devices.
“The activity of biological neurons and synapses is also controlled by electrical signals and ion migration, analogous to our magneto-ionic units,” says Spasojeviฤ.
In current neuromorphic systems, one challenging aspect is creating and adjusting synaptic weightsโthe strength of connections between artificial neurons. Vortions could serve this function, with their magnetization strength controlled by voltage to represent different connection strengths.
The energy efficiency of this approach is particularly noteworthy. Conventional methods for manipulating magnetic states often require substantial energy input through electrical currents or laser pulses. The voltage-based control of vortions consumes minimal power, aligning with the urgent need to reduce energy consumption in information technologies as data processing demands continue to grow.
Researchers believe that, besides their impact in brain-inspired devices, analog computing or multi-state data storage systems, vortions may have other potential applications, including medical therapy techniques, data security, magnetic spin computing devices, and the generation of spin waves.
In a world increasingly dominated by data-hungry technologies from artificial intelligence to the Internet of Things, innovations that increase computational efficiency while reducing energy consumption have never been more important. Voltage-controlled vortions may soon join the arsenal of technologies helping to meet these challenges, swirling their way into the future of computing with an energy-efficient spin.
Paper Summary
Methodology
The researchers created their experimental nanodots using electron beam lithographyโa technique that uses a focused beam of electrons to draw custom shapes on special materials sensitive to electrons. They started with silicon wafers coated with titanium and platinum layers, then applied a photoresist material that changes properties when exposed to electron beams. After exposure and development, they deposited a 35-nanometer layer of iron-cobalt-nitrogen (FeCoN) using a technique called magnetron sputtering. The resulting nanodots were 280 nanometers in diameterโabout 300 times thinner than a human hair.
To study the voltage-induced changes, they placed these nanodots in a custom-built electrochemical cell containing propylene carbonate with sodium and hydroxide ions. They applied voltages between the platinum layer beneath the nanodots and a counter electrode, creating an electric field that drove nitrogen ions either into or out of the nanodots. Throughout this process, they measured magnetic properties using magneto-optical Kerr effect (MOKE) magnetometry, which detects changes in reflected light due to magnetization.
Results
The study revealed several important discoveries. Initially, the FeCoN nanodots showed no permanent magnetism. When applying negative voltage (-25V), nitrogen ions gradually migrated out of the nanodots, creating magnetic regions. For short application times (about 6 minutes), the nanodots developed simple magnetic behavior where magnetization points uniformly in one direction. With longer application times, the magnetic behavior changed dramatically, showing the characteristic patterns of magnetic vortices.
The team discovered they could precisely control magnetic properties like resistance to demagnetization, the fields where vortices form and disappear, and most importantly, the strength of magnetization itself. The process proved fully reversibleโapplying positive voltage (+25V) caused nitrogen to reenter the nanodots, gradually returning them to their original non-magnetic state.
Detailed imaging revealed that nitrogen migration created a distinct boundary within each nanodot, dividing it into two distinct layers: a nitrogen-depleted magnetic layer at the bottom and a nitrogen-rich non-magnetic layer at the top.
Limitations
The research, while groundbreaking, has several limitations to consider. The current demonstration relied on liquid electrolytes, which aren’t practical for commercial electronic devices that would require solid-state solutions. The speed of nitrogen ion migration would need substantial improvement for practical computing applications that require rapid read/write operations.
The experiments were conducted under laboratory conditions with specialized equipment including synchrotron facilities, so translating the findings to practical, mass-producible devices represents a significant engineering challenge. Additionally, the relatively high voltages used (ยฑ25V) would need to be reduced for integration with conventional electronics.
Funding and Disclosures
This research was supported by the European Research Council through the 2021-ERC-Advanced REMINDS Grant, with additional funding from the Generalitat de Catalunya and the Spanish Government. The researchers utilized facilities at several institutions including the ALBA Synchrotron Light Facility in Spain, the Istituto Nazionale di Ricerca Metrologica in Italy, and Colorado State University in the USA. The authors declared no competing interests in relation to this work. The study brought together an international team of researchers from Spain, Italy, and the United States, combining expertise in materials science, magnetism, and advanced characterization techniques.
Publication Information
The study, titled “Magneto-ionic vortices: voltage-reconfigurable swirling-spin analog-memory nanomagnets,” was published in Nature Communications on February 26, 2025 (Volume 16, Article number 1990). The research was led by ICREA professor of the UAB Department of Physics Jordi Sort, and postdoctoral researcher of the UAB Department of Physics Irena Spasojevic as the first author of the publication. Other contributors included Zheng Ma from the UAB Department of Physics, Aleix Barrera and Anna Palau from the Institute of Materials Science of Barcelona (ICMAB-CSIC), and researchers from the ALBA Synchrotron, the Istituto Nazionale di Ricerca Metrologica (INRiM) of Turin, Italy, and Colorado State University, USA. The article is accessible under open access provisions through the Nature Communications website with the DOI identifier 10.1038/s41467-025-57321-8.
