Phys.org November 17, 2021 Magnetite has physical properties which may make it useful for spintronics technology. However, it is difficult to fabricate magnetite with high crystallinity owing to the imperfection of the substrate surface. An international team of researchers (Japan, China) has developed a chemical polishing technique—known by its acronym CARE—to prepare an atomically flat and highly ordered magnesium oxide substrate. CARE treatment of the substrate enabled the thin film to undergo a temperature-dependent resistivity change—known as the Verwey transition—of a factor of 5.9. The results have important applications – quantum computing technologies may rely on spintronics to optimize logistical, […]
Category Archives: Spintronics
Making progress towards quantum technologies based on magnetic molecules
Nanowerk October 15, 2021 Electrical control of spins at the nanoscale offers significant architectural advantages in spintronics. However, the electric-field sensitivities reported so far are rather weak. An international team of researchers (UK, Spain) showed that one path is to identify an energy scale in the spin spectrum that is associated with a structural degree of freedom with a substantial electrical polarizability. They studied an example of a molecular nanomagnet in which a small structural distortion establishes clock transitions in the spin spectrum; the fact that this distortion is associated with an electric dipole allowed them to control the clock-transition energy […]
New Exotic Magnetic Quasiparticle: “Skyrmion Bundle” Joins Topological Zoo
SciTech Daily August 23, 2021 Although theory has proposed “skyrmion bags” and “high-order skyrmions” as multi-Q topological magnetic structures, their experimental observations remain elusive. Using 3D micromagnetic simulation approach, an international team of researchers (China, USA – University of New Hampshire) proposed a new 3D multi-Q topological structure, skyrmion bundle. Through experimental verification they found collective motions and topological sign dependence of Hall sideway shifts of skyrmion bundles driven by nanosecond pulsed currents. Skyrmion bundles can serve as information carriers applied in distinct spintronic devices such as multi-state memory and information interconnect and should pave a new field of topological […]
Emergent magnetic monopoles controlled at room temperature
Phys.org August 6, 2021 3D nano-architectures are promising for the realization of 3D magnetic nano-networks for ultra-fast and low-energy data storage. Frustration in these systems can lead to magnetic monopoles, which can function as mobile, binary information carriers. However, Dirac strings in 2D artificial spin ices bind magnetic charges, while 3D dipolar counterparts require cryogenic temperatures for their stability. An international team of researchers (Austria, USA – Los Alamos National Laboratory) used micromagnetic simulations to demonstrate that the mobility threshold for magnetic charges is by 2 eV lower than their unbinding energy. By applying global magnetic fields, they steered magnetic charges […]
Transforming a van-der-Waals ferromagnet for future spintronics
Nanowerk June 28, 2021 An international team of researchers (Australia, China) demonstrated that ultra-high electron doping concentration (above 1021 cm-3) can be induced in the layered van der Waals (vdW) metallic material Fe5GeTe2 by proton intercalation and can further cause a transition of the magnetic ground state from ferromagnetism to antiferromagnetism. Compared to itinerant ferromagnets, antiferromagnets (AFMs) have unique advantages as building blocks of such future spintronic devices. Their robustness to stray magnetic fields makes them suitable for memory devices. All the samples showed that the ferromagnetic state can be gradually suppressed by increasing proton intercalation, and finally several samples […]
Controlling magnetization by surface acoustic waves
Nanowerk May 27, 2021 Interconversion between electron spin and other forms of angular momentum is useful for spin-based information processing. Well-studied examples of this are the conversion of photon angular momentum and rotation into ferromagnetic moment. Recently, several theoretical studies have suggested that the circular vibration of atoms work as phonon angular momentum; however, conversion between phonon angular momentum and spin-moment has yet to be demonstrated. Researchers in Japan demonstrated that the phonon angular momentum of surface acoustic wave can control the magnetization of a ferromagnetic Ni film by means of the phononic-to-electronic conversion of angular momentum in a Ni/LiNbO3 […]
Researchers report breakthrough that enables practical semiconductor spintronics
Phys.org April 8, 2021 By remote spin filtering of InAs quantum-dot electrons via an adjacent tunnelling-coupled GaNAs spin filter an international team of researchers (Sweden, Finland, Japan) demonstrated successful generation of conduction electron spin polarization exceeding 90% at room temperature without a magnetic field in a non-magnetic all-semiconductor nanostructure, which remains high even up to 110 °C. They also showed that the quantum-dot electron spin can be remotely manipulated by spin control in the adjacent spin filter, paving the way for remote spin encoding and writing of quantum memory as well as for remote spin control of spin–photon interfaces. This work […]
A new spin on energy-efficient electronics
Phys.org March 30, 2021 An international team of researchers (USA – University of Wisconsin, University of Nebraska, Cornell University, Lawrence Berkeley National Laboratory, Argonne National Laboratory, South Korea, UK, Norway, Ireland) designed a new structure based on antiperovskites to manipulate the flow of spin information without moving the electrons’ charges through the material. Through X-ray diffraction they figured out at what point the structure of the material changed, indicating the emergence of the necessary arrangement of electronic spins. The material develops a magnetic order a little above room temperature. According to the researchers the ability to manipulate the arrangement of […]
Catching electrons in action in an antiferromagnetic nanowire
Science Daily March 16, 2021 A team of researchers in the US (Michigan Technological University, Iowa State University) used a predictive quantum many-body theory that considers electron-electron interactions. The team found that chromium-doped nanowires with a germanium core and silicon shell can be an antiferromagnetic semiconductor. The origin of antiferromagnetic spin alignments between Cr is attributed to the super exchange interaction mediated by the pz orbitals of the Ge atoms that are bonded to Cr. A weak spin–orbit interaction in this material, suggested a longer spin coherence length. The spin-dependent quantum transport calculations in the Cr-doped nanowire junction revealed a […]
Spintronics: New production method makes crystalline microstructures universally usable
Science Daily February 23, 2021 Based on a recently developed method that allows the fabrication of freestanding monocrystalline YIG bridges on gadolinium-gallium-garnet, researchers in Germany have developed a process that allows the transfer of monocrystalline yttrium-iron-garnet microstructures onto virtually any kind of substrate. The bridges’ spans are detached from the substrate by a dry etching process and immersed in a watery solution. Using drop-casting, the immersed YIG platelets can be transferred onto the substrate of choice, where the structures finally can be reattached and, thus, be integrated into complex devices or experimental geometries. They demonstrated that the structures retain their […]