In today’s technology-driven world, our demand for faster and more efficient computing has never been higher. From smartphones and laptops to advanced artificial intelligence, the need for greater processing power continues to grow. To meet this ever-increasing demand, researchers and scientists are exploring innovative approaches beyond traditional electronics. One of the most promising fields is spintronics, an area that uses both the charge and the spin-orientation of electrons to revolutionize information storage, processing, and transmission.
Traditional electronics have relied on the charge of electrons to carry and store information. In contrast, spintronic devices harness an additional property of the electron: its spin. This spin is a quantum mechanical property that essentially describes the electron’s intrinsic magnetic moment, akin to how a spinning top behaves. By assigning specific values to the spin orientation—typically “up” as 0 and “down” as 1—spintronic devices offer the potential for ultra-fast, more energy-efficient computing platforms. Physicists believe that exploring this added dimension of electron behavior could provide solutions to the modern world’s computing challenges.
A Quantum Leap in Understanding: Spin-Torque
One critical factor that drives the success of spintronics is the ability to manipulate the electron’s spin in a controlled manner. This is where the concept of spin-torque comes in, a vital property for electrical manipulation of magnetization within materials. Magnetic properties are at the heart of data storage technologies, especially in devices like hard drives and magnetic random access memory (MRAM). The ability to change the direction of magnetization electrically—without relying on traditional external magnetic fields—opens the door to faster and more efficient computing.
To truly unlock the potential of spintronics, physicists must delve into the underlying quantum mechanical properties of the materials they are studying. One such property is spin-torque, an effect in which the flow of electrical current can generate torque, altering the spin orientation of electrons. This understanding is crucial for advancing storage and processing technologies. If scientists can fine-tune these properties, they will pave the way for creating next-generation spintronic devices that could operate at unparalleled speeds and efficiencies.
New Frontiers: The Anomalous Hall Torque
A significant breakthrough in spintronics occurred on January 15, 2025, when researchers at the University of Utah, in collaboration with the University of California, Irvine (UCI), announced the discovery of a new type of spin–orbit torque. Published in Nature Nanotechnology, their work introduced an innovative method of manipulating spin and magnetization through electrical currents. They named this phenomenon the anomalous Hall torque, expanding the spintronic toolbox and offering new avenues for device applications.
Eric Montoya, assistant professor of physics and astronomy at the University of Utah and lead author of the study, emphasized the significance of this discovery: “This is brand new physics, which on its own is interesting, but there’s also a lot of potential new applications that go along with it.” The anomalous Hall torque could open new possibilities for computing systems that mirror the efficiency and complexity of human brain networks, such as in neuromorphic computing. This nascent field aims to mimic the brain’s functionality and is expected to drive advancements in machine learning and artificial intelligence.
The Basics of Spin and Torque: Unveiling the Hall Effect
Before diving into the specifics of the anomalous Hall torque, it’s essential to understand the basic mechanics of electron spins and how they can be manipulated. Electrons, like small magnets, have a property called magnetic dipole moments. These can either be oriented “up” or “down,” much like a bar magnet’s north and south poles. This inherent magnetic characteristic of electrons allows for the possibility of torque—a rotational force on the electron spin.
One of the core ideas in spintronics is the fact that external electric currents can be used to sort electrons based on their spin orientation. This sorting occurs through what is known as symmetry, the specific manner in which electron spins are distributed within a material. The arrangement of these spin orientations can influence the material’s magnetic properties, such as the way a ferromagnet’s magnetic field flows.
The concept of Hall effects helps explain how electrons move within a magnetic field. The well-known anomalous Hall effect, discovered in 1881 by physicist Edwin Hall, describes how the flow of electrons in a magnetic material creates an asymmetry that leads to a voltage perpendicular to the current. The anomalous Hall torque is conceptually similar, but instead of creating charge flow, it generates a spin current when an external electrical current is applied to a material, driving the spin current 90 degrees to the current’s path. This result is essential for enabling spin manipulation via electrical means.
Eric Montoya noted, “It really comes down to the symmetry. The different Hall effects describe the symmetry of how efficiently we can control the spin-orientation in a material.” In essence, the Hall effects provide a way to understand how to control the behavior of spin in various materials, an ability critical for building more efficient spintronic devices.
The Triad of Spin-Orbit Torques
The discovery of the anomalous Hall torque has profound implications for the field of spintronics, especially when viewed in the context of other spin-torque effects. Montoya and his colleagues highlight this broader framework by introducing a triad of spin–orbit torques, comprising the anomalous Hall torque, the spin Hall torque, and the planar Hall torque. These three Hall-like effects, all related to spin–orbit interactions, form what the team has termed the Universal Hall Torques.
These torques share a common ability to manipulate the spin of electrons electrically, opening up an essential toolset for scientists working to develop spintronic devices. As these torques are present across various conductive materials, they are likely to be applicable to a wide range of spintronic applications. Researchers could use these torques to fine-tune the operation of spintronic devices to support the rapidly growing demands for faster and more efficient computing.
In traditional spintronics systems, devices typically consist of a non-magnetic layer placed between two ferromagnetic layers. These systems, like Magnetoresistive Random Access Memory (MRAM), rely on a spin-polarized current that flows from one magnetic layer to another, flipping the magnetic orientation and thus storing data in binary form (0s and 1s).
However, in their recent work, the authors demonstrated a breakthrough by showing that the anomalous Hall torque could allow for the transfer of spin-orientation between a ferromagnetic conductor and an adjacent non-magnetic material. This eliminates the need for an additional ferromagnetic layer, leading to a simpler, more efficient spintronic architecture. Their prototype device, which uses the anomalous Hall torque effect, represents an exciting step forward in both spintronics and the broader field of memory and data storage technologies.
The Future: Toward Neuromorphic Computing
One of the most exciting potential applications of this discovery is in the realm of neuromorphic computing. Neuromorphic systems are designed to replicate the neural structures and functions of the human brain, enabling much more efficient and adaptive computing systems. These systems have significant potential for artificial intelligence, deep learning, and other advanced cognitive technologies.
The study demonstrated that the anomalous Hall torque effect could be leveraged to create a spin-torque oscillator, a nanoscale device that mimics the behavior of a neuron. Unlike traditional neuromorphic systems, which are large and power-hungry, these spin-based devices would be significantly smaller and faster. As Ilya Krivorotov, a co-author of the study, explained, “Our next step is to interconnect these devices into a larger network, enabling us to explore their potential for performing neuromorphic tasks, such as image recognition.”
Through this work, the researchers are not just breaking ground in basic physics but also laying the foundation for systems that could power the next generation of AI-driven technologies. Spintronic devices, with their low energy consumption and high speed, could one day serve as the core of efficient, brain-inspired computing architectures.
Conclusion: Toward a Spintronic Revolution
The field of spintronics is on the verge of a revolution, with new discoveries like the anomalous Hall torque opening up a myriad of possibilities for more powerful, energy-efficient devices. As the researchers from the University of Utah and UCI have shown, understanding and controlling the spin-orientation of electrons can lead to a new generation of storage technologies, as well as powerful computing systems modeled after the human brain.
With the continued development of these spin-orbit torques, the world of spintronics holds promise for technologies that are not only faster and more efficient but also capable of performing complex tasks like neuromorphic computing. As we advance into this new frontier of electronics, we may look back at these breakthroughs as the foundation for a new era in computing—one that takes full advantage of the quantum properties of materials to meet the ever-growing demands of the digital world.
Reference: Eric Arturo Montoya et al, Anomalous Hall spin current drives self-generated spin–orbit torque in a ferromagnet, Nature Nanotechnology (2025). DOI: 10.1038/s41565-024-01819-7