Scientists in the US have discovered that hematite features a rare new form of magnetism, which reportedly paves the way for spintronics technology that could transform data processing and storage.
The discovery, made by researchers at Oak Ridge National Laboratory (ORNL), provided one of the clearest experimental evidence of alternating magnetism, a newly confirmed third form of magnetism first proposed in 2022.
Hematite, an abundant iron oxide known as rust, is one of the most common minerals on Earth. It is stable above 1,200 degrees Fahrenheit, making it ideal for room-temperature spintronics that do not require intensive cooling.
“Hematite is abundant, chemically stable, and nontoxic,” said ORNL project leader and postdoctoral researcher Qiyang Sun, Ph.D. “By confirming its alternating current magnetic properties, we open a new platform for engineers to design high-speed, low-power quantum electronics using inexpensive and widely available materials.”
Inside the quantum state of hematite
AC magnets are magnetic materials in which electron spins align in opposite directions, unlike traditional antiferromagnets. This allows pure spin current to flow without charge, making it ideal for spintronics applications.
Spintronics (magnetoelectronics), on the other hand, is a technology that relies on the spin of electrons rather than their charge to process and store data, potentially enabling devices that operate at high speeds and consume far less energy than modern electronics.
However, identifying practical and suitable materials for spintronics applications remains a major challenge so far. Now, to examine hematite’s properties, researchers turned to one of the world’s most advanced neutron research facilities: the Spallation Neutron Source (SNS).
In the field, the team used a technique known as inelastic neutron scattering. Inelastic neutron scattering is defined as an event in which neutrons lose or gain energy by transferring energy to form a sample. In this way, scientists investigated the internal magnetodynamics of materials at the atomic level.
Although neutrons have no electric charge, they do have a magnetic moment, making them very suitable for studying magnetism. The researchers thus analyzed spin waves, collective excitations that travel through the magnetic structure of matter.
Powering future technology
The results showed that the energies of these spin waves were clearly split, a subtle but crucial sign of variable magnetism. This phenomenon, called magnon splitting, cannot be captured by other experimental techniques.
“Inelastic neutron scattering is the only method that can resolve these fine spectral features,” Sun said. “This gives us simultaneous momentum and energy resolution, allowing us to detect the subtle magnon splitting that defines alternating current magnetism.”
The study combined modeling and experimentation using ORNL’s Sunny software and high-performance computing. This software was built to study quantum magnetism.
“The confirmation of variable magnetism in hematite, a material as common as rust, indicates that the potential elements of the next revolution in high-speed, low-power quantum electronics may already be all around us,” Sun concluded in a press release.
Researchers say this discovery has the potential to reshape electronic design. They believe that charge-free spin currents can reduce energy loss and heat, increasing efficiency. Future studies will investigate how the spin wave gap affects heat transport in hematite.
The study was published in the journal physical review letter.
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