Recent Spintronic News - Page 4

An international research team led by the Technical University of Denmark (DTU) has developed a new magnetic material that combines a robust internal magnetic structure with an almost vanishing external magnetic field, and it maintains these properties well above room temperature. 

The material is the molecular framework Cr(pyrazine)₃, a three-dimensional cubic ReO₃‑type structure in which Cr³⁺ ions are bridged exclusively by pyrazine radical anions. In this architecture, the chromium centers and the pyrazine radicals form two magnetic sublattices whose moments are strongly antiferromagnetically coupled, giving rise to a nearly perfectly compensated ferrimagnetic ground state with an exceptionally small net magnetic moment.

Researchers from the Tokyo University of Science, Kyoto Institute of Technology, University of Tsukuba and National Institute for Materials Science (NIMS) have developed an interpretable machine-learning framework that automatically detects anomalies in Fermi surface maps of the spintronic Heusler alloy Co₂MnGaₓGe₁₋ₓ (CMGG). The approach uses principal component analysis (PCA) on simulated Fermi-surface images to pinpoint compositions where the electronic structure changes sharply, and links these anomalies directly to nodal-line formation and variations in spin polarization.

In this work, the team focuses on CMGG, a Heusler alloy with half-metallicity, nodal-line features and high spin polarization, known for its anomalous Nernst effect arising from nodal lines on the Fermi surface. Using density functional theory (DFT), they first generate a composition-dependent band-structure dataset and extract kₓ–kᵧ Fermi-surface cuts through the Γ point. These images are blurred to roughly approximate ARPES data, then converted into one-dimensional vectors and analyzed via PCA to obtain a low-dimensional representation where each point corresponds to a specific Ga content x.

Researchers from the Hebrew University of Jerusalem, University of Southern California, RPTU Kaiserslautern-Landau, Johannes Gutenberg-Universitat Mainz, Ariel University, California Institute of Technology, Uppsala University and the Weizmann Institute have reported a spin-dependent mechanism that may resolve one of the longest-standing questions in science: not only how homochirality emerged, but why a specific handedness was selected.

For more than 150 years, scientists have sought to understand why biological systems exclusively use one enantiomeric form - D-type for RNA and specific handedness for amino acids - despite the near-identical chemical properties of mirror-image molecules. Previous work established that homochirality could arise via enantioselective interactions with magnetic substrates, such as magnetite, through the chirality-induced spin selectivity (CISS) effect. However, this framework did not explain why one enantiomer is ultimately favored over the other.

Researchers from Freie Universität Berlin, Uppsala University and Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) have directly tracked how magnetic order in a coupled Fe/CoO bilayer collapses within a few hundred femtoseconds after an ultrashort laser pulse, and identified interfacial energy transfer from Fe to CoO as the key channel for quenching the antiferromagnetic order.

The sample consists of an epitaxial 9 (±0.5) monolayer CoO film on Ag(001), capped by 9 (±1) monolayers of Fe. The CoO antiferromagnetic moments are collinear in the film plane and aligned with the Fe magnetization along an Fe ⟨100⟩ easy axis due to strong interfacial coupling; an external magnetic field can rotate this AFM spin axis by 90° in the plane via the Fe layer. Time-resolved measurements were carried out at BESSY II using 60 fs p‑polarized pump pulses at 800 or 400 nm and 100 fs polarized soft x‑ray probe pulses, providing 120 fs temporal resolution in a pump–probe reflection geometry under ultrahigh vacuum at 200 K and a 120 mT in‑plane field.

Researchers from Nankai University, South China Normal University and additional institutes have introduced a new approach to precisely and rapidly switch the helicity of magnetic vortices.

Their novel method involves the use of extremely short laser pulses and a magnetic field applied perpendicular to the surface of a nano-engineered material. As part of their study, the researchers first engineered tiny magnetic vortices in a magnetic material made up of 80% of nickel (Ni) and 20% iron (Fe). This magnetic alloy is promising for the development of spintronics as it possesses advantageous magnetic properties.

Everspin Technologies has announced a strategic manufacturing agreement with Microchip Technology to expand on-shore production of its MRAM and tunnel magnetoresistive (TMR) sensor products. The initial 10-year deal, which can be extended in two-year increments, will see Everspin establish a copy exact (plus) MRAM line at a Microchip semiconductor fabrication facility in Oregon, mirroring its existing line in Chandler, Arizona.

Under the agreement, Everspin will transfer its magnetic technology and MRAM manufacturing process into Microchip’s Oregon fab while retaining ownership of its spintronic IP and process know-how, using Microchip’s foundry capacity to scale output. This added line is designed to increase wafer capacity for MRAM and TMR devices, provide a fully on-shore second source, and support long-term supply continuity for spintronics-based non-volatile memory and sensor products well into the next decade.

Researchers from Penn State, University of Oxford, Zhejiang University, Diamond Light Source and the University of North Texas have engineered an atomically confined gallium trilayer between graphene and silicon carbide that hosts robust Ising‑type superconductivity under strong in‑plane magnetic fields. This interface‑driven superconducting state in a light‑element heterostructure opens intriguing opportunities for integrating superconductivity with spin‑based functionalities in future spintronics devices.

The device consists of just three atomic layers of gallium sandwiched between a graphene overlayer and a 6H‑SiC(0001) substrate, grown using plasma‑free confinement epitaxy assisted by a carbon buffer layer. Within this ultra‑thin “quantum well,” superconductivity emerges at low temperatures, while the graphene capping layer protects the gallium from oxidation and contamination and the SiC substrate provides a structurally and electronically active interface. The result is a clean, strongly confined 2D superconducting channel whose properties are dominated by interfacial quantum interactions.

Researchers from University College London, University of Leeds, Tohoku University, Imperial College London and Japan Atomic Energy Agency have demonstrated that spin transfer torques in nearly isotropic CoFeB-based magnets can dynamically stabilize magnetic states that are unstable in equilibrium, realizing a nanoscale spintronic analogue of the Kapitza pendulum.

The team uses MgO∣CoFeB∣W multilayers, where the demagnetizing field favors in-plane magnetization while an interface-induced perpendicular magnetic anisotropy (PMA), tuned by post-growth annealing, counter-balances this tendency. By carefully optimizing the growth-annealing protocol, the shape and interface anisotropies almost cancel, yielding magnets with vanishingly small effective anisotropy that are nearly isotropic on the Bloch sphere. This near-isotropy is crucial because it suppresses conventional auto-oscillations and lowers the critical current needed to drive the system into a strongly nonlinear dynamical regime.

Researchers from the University of Maryland, University of California, South Dakota School of Mines and Technology, East China Normal University, KAUST and other institutes recently reported all‑van der Waals multiferroic tunnel junctions (MFTJs) that combine ferromagnetism and ferroelectricity in a single nanoscale spintronic device, enabling four non‑volatile resistance states for multibit memory operation. 

These multistate junctions are realized by vertically stacking three atomically thin crystals: two ferromagnetic electrodes and a ferroelectric tunnelling barrier, all obtained by mechanical exfoliation and then assembled into a clean, defect‑sparse heterostructure. In their prototypical structure, Fe₃GeTe₂/CuInP₂S₆/Fe₃GeTe₂, multilayer Fe₃GeTe₂ serves as the ferromagnetic electrodes, while CuInP₂S₆ (CIPS) provides a ferroelectric spacer with switchable polarization. Because the layers are coupled by van der Waals forces rather than epitaxial bonding, the stack avoids stringent lattice‑matching and chemical‑compatibility constraints that hinder oxide‑based MFTJs and is far less susceptible to interfacial defects and interdiffusion.

A team of scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, Northwestern University, the University of Edinburgh, the Donostia International Physics Center and the University of Arkansas has revealed how magnetic domains behave inside 2D van der Waals magnets based on Fe₃GeTe₂ (FGT), providing a roadmap for tuning skyrmions using material thickness and magnetic‑field conditions. 

The researchers worked with a thin, layered FGT flake whose thickness changed gradually across the sample, creating regions that behave differently magnetically while still being part of the same crystal. Because FGT in this study is magnetic only at low temperature, the flake was cooled with liquid nitrogen to cryogenic temperatures while an out‑of‑plane magnetic field was applied (field cooling), setting up well‑defined initial domain patterns.