Phys.org February 14, 2024 Altermagnets have a special combination of the arrangement of spins and crystal symmetries. The spins alternate, as in antiferromagnets, resulting in no net magnetization. Rather than simply canceling out, the symmetries give an electronic band structure with strong spin polarization that flips in direction as you pass through the material’s energy bands resulting in highly useful properties more resemblant to ferromagnets, as well as some completely new properties. An international team of researchers (Switzerland, Germany, Czech Republic, Austria, Colombia, UK) has proved the existence of altermagnetism. They provided the confirmation using photoemission spectroscopy and ab initio […]
Tag Archives: Spintronics
Controlling waves in magnets with superconductors for the first time
Science Daily October 26, 2023 For spintronics spin-waves have emerged as a promising platform that can offer new functionalities because of their wave nature. However, control of the spin-waves has remained a formidable challenge. Researchers in the Netherlands used superconducting diamagnetism to shape the magnetic environment governing the transport of spin waves in a thin-film magnet. Using diamond-based magnetic imaging, they observed hybridized spin-wave–Meissner-current transport modes with strongly altered, temperature-tunable wavelengths and then demonstrated local control of spin-wave refraction using a focused laser. According to the researchers their results demonstrate the versatility of superconductor-manipulated spin-wave transport and have potential applications […]
Researchers demonstrate solution for long-term challenge, bringing benefits to spintronics and data storage technologies
Phys.org October 30, 2023 Transition-metal oxides (TMOs) with strong ferrimagnetism provide new platforms for tailoring the anomalous Hall effect (AHE) beyond conventional concepts based on ferromagnets, and particularly TMOs with perpendicular magnetic anisotropy (PMA) are of prime importance for today’s spintronics. In this study researchers in Germany reported on transport phenomena and magnetic characteristics of the ferrimagnetic TMO NiCo2O4 (NCO) exhibiting PMA. The entire electrical and magnetic properties of NCO films were strongly correlated with their conductivities governed by the cation valence states. The AHE exhibited an unusual sign reversal resulting from a competition between intrinsic and extrinsic mechanisms depending […]
New material could hold key to reducing energy consumption in computers and electronics
Nanowerk July 13, 2023 Contrary to topological insulators, topological semimetals possess a nontrivial chiral anomaly that leads to negative magnetoresistance and host to both conductive bulk states and topological surface states with intriguing transport properties for spintronics. Researchers at the University of Minnesota fabricated highly ordered metallic Pt3Sn and Pt3SnxFe1-x thin films via sputtering technology. Systematic angular dependence (both in-plane and out-of-plane) study of magnetoresistance presented surprisingly robust quadratic and linear negative longitudinal magnetoresistance features for Pt3Sn and Pt3SnxFe1-x, respectively. They attributed the anomalous negative longitudinal magnetoresistance to the type-II Dirac semimetal phase (pristine Pt3Sn) and/or the formation of tunable […]
Hydrogen-tuned topological insulators may lead to new platforms in sustainable quantum electronics
Phys.org May 4, 2022 An international team of researchers (USA – City College of New York, Virginia Tech, Oak Ridge National Laboratory, City University of New York, Poland) invented a new facile and powerful technique that uses ionic hydrogen to reduce charge carrier density in the bulk of 3D topological insulators and magnets. It made robust non-dissipative surface or edge quantum conduction channels accessible for manipulation and control. Hydrogen-tuning technique of chalcogen-based topological materials and nanostructures uses insertion and extraction of ionic hydrogen from dilute aqueous hydrochloric acid solution, which leaves the layered topological crystal structure as well as electronic […]
New quantum dots for quantum networks
Phys.org April 7, 2022 Spin can be also used as the medium for quantum communication by transferring quantum information with light. But the process of transferring information to the spin of extremely small electrons is challenging and must be performed efficiently. An international team of researchers (Japan, Canada, Germany) has realized the world’s first GaAs gate-controlled quantum dot circuit on a (110)-oriented surface that promises to increase photon-electron spin conversion efficiency. This has the effect of encoding quantum information from incident photons into the electron spins. Because of the way the hole interacts with the GaAs crystal lattice, the g-factor, […]
New materials for quantum technologies
Phys.org December 22, 2021 To advance spintronics devices and quantum information technology using materials with non-trivial topological properties, three key challenges are still unresolved – the identification of topological band degeneracies located at the Fermi level, the ability to easily control such topological degeneracies., and the identification of generic topological degeneracies in large, multisheeted Fermi surfaces. Researchers in Germany have shown that the non-symmorphic symmetries in chiral, ferromagnetic manganese silicide (MnSi) generate nodal planes (NPs) which enforce topological protectorates (TPs) with substantial Berry curvatures at the intersection of the NPs with the Fermi surface (FS) regardless of the complexity of […]
Scientists successfully manipulate a single skyrmion at room temperature
Nanowerk December 17, 2021 The key to creating spintronics devices is the ability to effectively manipulate, and measure, a single skyrmion. Researchers in Japan used a thin magnetic plate made up of a compound of cobalt, zinc, and manganese, Co9Zn9Mn2 to observe the dynamics of a single skyrmion at room temperature. They were able to track the motions of the skyrmion and control its Hall motion directions by flipping the magnetic field when they subjected it to ultrafast pulses of electric current—on the scale of nanoseconds. They found that the skyrmion’s motion demonstrated a dynamic transition from a pinned static […]
Molecular interfaces for innovative sensors and data storage devices
Nanowerk October 20, 2021 To better understand electronic and magnetic properties and understanding the mechanisms that govern the interactions at the interface an international team of researchers (Germany, Austria, Switzerland, Italy) coupled nickel-porphyrin with copper. Using theoretical and experimental spectro-microscopy approach they showed that the charge transfer occurring at the interface between nickel tetraphenyl porphyrins and copper changes both spin and oxidation states of the Ni ion. The chemically active Ni(I), even in a buried multilayer system, can be functionalized with nitrogen dioxide, allowing a selective tuning of the electronic properties of the Ni center that is switched to a […]
Quantum material to boost terahertz frequencies
Science Daily October 20, 2021 An international team of researchers (Germany, Spain, Russia) investigated the ultrafast carrier dynamics in topological insulators (TIs) of the bismuth and antimony chalcogenide family, where they isolated the response of Dirac fermions at the surface from the response of bulk carriers by combining photoexcitation with below-bandgap terahertz (THz) photons and TI samples with varying Fermi level, including one sample with the Fermi level located within the bandgap. They identified distinctly faster relaxation of charge carriers in the topologically protected Dirac surface states, compared to bulk carriers and they observed THz harmonic generation without any saturation […]