Articles tagged with "spintronics"
First self-powered quantum microwave signal achieved in experiment
Researchers from Vienna University of Technology (TU Wien) and Okinawa Institute of Science and Technology (OIST) have experimentally demonstrated the first self-induced superradiant masing—microwave signal generation without external driving forces. Superradiance, a quantum optics phenomenon where atoms or quantum dots emit intense, coherent light pulses collectively, was traditionally associated with energy loss and short bursts. However, the team observed a novel behavior where quantum particles, specifically electron spins in nitrogen-vacancy (NV) centers within diamond ensembles, self-sustain long-lived, stable microwave pulses through intrinsic spin–spin interactions. This self-organization from seemingly disordered spin interactions produces a coherent microwave signal, revealing a fundamentally new mode of collective quantum behavior. The discovery challenges previous assumptions that interactions among quantum particles disrupt coherence, showing instead that these interactions can fuel and maintain quantum emission. Large-scale computational simulations confirmed that spin interactions continually repopulate energy levels, sustaining the superradiant reaction over extended periods. This breakthrough opens new avenues for
quantum-technologymicrowave-signalssuperradianceenergy-harvestingquantum-sensorsquantum-materialsspintronicsScientists identify new magnetic state for future data storage
Researchers from several Japanese institutions, including the National Institute for Materials Science and Tohoku University, have experimentally demonstrated a rare magnetic state called altermagnetism in ruthenium dioxide (RuO₂) thin films. By precisely controlling the crystal orientation of RuO₂ films grown on sapphire substrates, the team was able to reveal this third fundamental class of magnetism, which combines advantages of ferromagnets and antiferromagnets. Unlike ferromagnets, altermagnets have no net magnetization, reducing interference issues in miniaturized devices, yet unlike antiferromagnets, they allow electrical readout of spin-dependent signals, making them promising for spintronics and data storage applications. The researchers used X-ray magnetic linear dichroism to map the spin arrangement and confirmed spin-split magnetoresistance, providing strong evidence of altermagnetism’s unique spin-split electronic structure. Their approach of aligning the crystal lattice uniformly was key to observing these subtle magnetic effects
materialsmagnetic-materialsaltermagnetismRuO2-thin-filmsdata-storagespintronicsmemory-technologyStudy overturns 180-year physics rule about light–matter interaction
materialslight-matter-interactionFaraday-Effectmagnetismoptical-physicsTerbium-Gallium-GarnetspintronicsNew 2D magnetic transistor delivers 10x stronger current switching
MIT engineers have developed a novel magnetic transistor using a two-dimensional magnetic semiconductor, chromium sulfur bromide, which enables current switching that is ten times stronger than existing magnetic transistor designs. This device operates with significantly lower energy compared to traditional silicon transistors, overcoming silicon’s voltage limitations that hinder further efficiency improvements. The magnetic semiconductor’s stable structure allows precise switching between two magnetic states, altering its electronic behavior and enabling low-energy operation. The team’s innovative fabrication method, which avoids solvents or glue by directly transferring the thin magnetic film onto a silicon substrate with tape, results in a clean interface that enhances device performance. Beyond stronger and more energy-efficient switching, the new transistor uniquely integrates logic and memory functions, allowing it to store information directly rather than relying on separate magnetic memory cells. This built-in memory capability, combined with faster and more reliable readouts due to the stronger signal, represents a significant advancement for spintronic devices. The researchers demonstrated control of the magnetic state both via external magnetic fields and electrical currents,
materialsspintronicsmagnetic-transistor2D-materialssemiconductor-physicslow-energy-electronicsmemory-devicesUS team sees tiny spinning waves called magnons moving in magnets
A research team at Brookhaven National Laboratory has achieved the first direct observation of magnon spin currents using resonant inelastic X-ray scattering (RIXS), marking a significant advancement in spintronics. Unlike previous methods that detected spin currents indirectly by converting them into electrical signals, this approach allowed scientists to measure the momentum distribution of magnons—quantized spin excitations carrying angular momentum—in a magnetic insulator (yttrium iron garnet, YIG) under a temperature gradient. The RIXS technique was sensitive enough to detect subtle imbalances in magnon intensity, providing a microscopic view of how magnons move and carry spin current without involving electron charge transport. This breakthrough is crucial for developing future energy-efficient spintronic devices, which rely on controlling spin currents to store and transmit information at higher densities. By applying a mathematical model, the team could calculate magnon lifetimes and dynamics, offering insights essential for magnon-based technologies. The researchers plan to extend their work to thin films
spintronicsmagnonsmagnetic-materialsenergy-efficient-technologyyttrium-iron-garnetspin-currentsresonant-inelastic-X-ray-scatteringNon-magnetic material shows 'Anomalous Hall Effect' for the first time
Japanese physicists from the Tokyo Institute of Science and Technology have experimentally observed the Anomalous Hall Effect (AHE) in a nonmagnetic material—cadmium arsenide (Cd3As2)—for the first time, confirming longstanding theoretical predictions. Traditionally, AHE was believed to occur only in magnetic materials due to electron spin magnetization. However, the team demonstrated a large AHE signal in pure thin films of Cd3As2 by applying an in-plane magnetic field and carefully manipulating the electronic band structure to isolate the anomalous contribution from the ordinary Hall effect. This discovery overturns the assumption that AHE is exclusively spin-driven. The significance of this finding lies in the origin of the AHE in Cd3As2, which arises from orbital magnetization—the circular orbital motion of electrons—rather than spin magnetization typical of ferromagnets. This highlights the often-overlooked role of orbital effects in electron behavior and opens new avenues for both fundamental research and technological applications. Potential
materialsanomalous-hall-effectcadmium-arsenidedirac-semimetalsmolecular-beam-epitaxyelectronic-band-structurespintronicsWrinkled 2D sheets may unlock faster, more efficient devices
Researchers at Rice University have discovered that tiny wrinkles in two-dimensional (2D) materials, such as molybdenum ditelluride, can precisely control electron spin, a quantum property that could revolutionize computing. Unlike traditional devices that rely on electron charge, spintronics uses electron spin states ("up" or "down") to process information, potentially enabling faster, smaller, and more energy-efficient devices. A major challenge in spintronics has been the rapid decay of spin information due to electron scattering, but the Rice team found that bending 2D materials creates a unique spin texture called a persistent spin helix (PSH), which preserves spin states even amid collisions. This effect arises from the flexoelectric polarization generated by uneven strain when the 2D sheet is bent—stretching on one side and compressing on the other—creating internal electric fields that split spin-up and spin-down electrons into distinct bands. The curvature-induced interaction is strongest in highly curved regions like wrinkles or
materials2D-materialsspintronicsenergy-efficient-deviceselectron-spinquantum-computingflexoelectric-polarizationNew framework clears spin-orbit confusion in solids and unifies physics
Physicists have developed a new theoretical framework that resolves longstanding difficulties in modeling spin-orbit coupling in solids, a phenomenon where an electron’s spin and motion are intertwined. Traditional quantum mechanical tools, particularly the orbital angular momentum operator, fail to accurately describe electron behavior in crystalline solids due to the lack of full rotational symmetry in atomic lattices. The new approach, termed relativistic spin-lattice interaction, bypasses these issues by focusing on how an electron’s spin interacts with the solid’s atomic structure using principles from relativity. This method aligns well with standard descriptions of electrons in crystals and respects the periodic atomic arrangement, overcoming limitations of earlier models. The researchers validated their framework across materials of different dimensionalities—a 3D semiconductor (gallium arsenide), a 2D insulator (hexagonal boron nitride), and a 1D conductor (atomic chains)—demonstrating improved accuracy in predicting spin behavior and reproducing key phenomena such as the Edelstein and spin Hall effects.
materialsspintronicsquantum-mechanicsspin-orbit-couplingelectron-spinsolid-state-physicsspin-lattice-interactionQuantum miracle: Graphene shows spin currents without any magnets
Researchers at Delft University of Technology have achieved a groundbreaking feat by generating and detecting quantum spin currents in graphene without the use of external magnetic fields. Traditionally, inducing the quantum spin Hall (QSH) effect in graphene required strong magnetic fields, which are impractical for on-chip integration. By placing graphene atop a layered magnetic material called chromium thiophosphate (CrPS₄), the team harnessed magnetic proximity effects to induce spin-orbit coupling and exchange interactions in graphene. This combination opened an energy gap and enabled electrons to flow along graphene’s edges with aligned spins, demonstrating the QSH effect in a magnet-free environment. In addition to observing the QSH effect at cryogenic temperatures, the researchers discovered an anomalous Hall (AH) effect that persisted even at room temperature, where electrons deflect sideways without an external magnetic field. The coexistence of these effects suggests practical pathways for developing ultrathin, spin-based quantum devices. The stable, topologically protected spin currents in graphene could facilitate long-distance
graphenespintronicsquantum-devicesmaterials-scienceenergy-efficient-electronicsquantum-spin-Hall-effectmagnetic-proximity-effectNew form of magnetism discovered promises faster, denser memory tech
materialsmagnetismenergy-efficientmemory-devicesspintronicselectronic-spinsultrafast-technology