Science Daily February 11, 2022 An international team of researchers (UK, Japan) used monolayer graphene encapsulated by hexagonal boron nitride in van der Waals heterostructure with one-dimensional contacts. They measured electron mobility up to 130,000cm2/Vs at low temperatures (20K or -253oC) and spin diffusion lengths approaching 20 μm. The nanoscale-wide 1D contacts allow spin injection both at room and at low temperature, with the latter exhibiting efficiency comparable with 2D tunnel contacts. At low temperature, the spin signals can be enhanced by as much as an order of magnitude by electrostatic gating, adding new functionality. According to the researchers the […]
Category Archives: Spintronics
Two-dimensional material could store quantum information at room temperature
Phys.org February 11, 2022 Spins in two-dimensional materials offer an advantage, as the reduced dimensionality enables feasible on-chip integration into devices. An international team of researchers (UK, Australia) has reported room-temperature optically detected magnetic resonance (ODMR) from single carbon-related defects in hexagonal boron nitride with up to 100 times stronger contrast than the ensemble average. They identified two distinct bunching timescales in the second-order intensity-correlation measurements for ODMR-active defects, but only one for those without an ODMR response. They observed either positive or negative ODMR signal for each defect. Based on kinematic models, they related this bipolarity to highly tunable […]
New data-decoding approach could lead to faster, smaller digital tech
Phys.org December 28, 2021 An international team of researchers (USA – University of Nebraska, University of Wisconsin, China) has shown that spin-independent conductance in compensated antiferromagnets and normal metals can be efficiently exploited in spintronics, provided their magnetic space group symmetry supports a non-spin-degenerate Fermi surface. Due to their momentum-dependent spin polarization, such antiferromagnets can be used as active elements in antiferromagnetic tunnel junctions (AFMTJs) and produce a giant tunneling magnetoresistance (TMR) effect. Using RuO2 as a representative compensated antiferromagnet exhibiting spin-independent conductance they designed a RuO2/TiO2/RuO2 (001) AFMTJ, where a globally spin-neutral charge current was controlled by the two […]
Memristive spintronic neurons: Combining two cognitive computing nano-elements into one
Nanowerk December 6, 2021 For ultrafast non-conventional computing synchronization of large spin Hall nano-oscillator arrays tuning its individual oscillators and providing built-in memory units remain substantial challenges. An international team of researchers (Sweden, India, Japan) has demonstrated the integration of a memristor into another, a spintronic oscillator. Arrays of the memristor-controlled oscillators combine the non-volatile local storage of the memristor function with the microwave frequency computation of the nano-oscillator networks and can closely imitate the non-linear oscillatory neural networks of the human brain. Using the memristor-controlled spintronic oscillator arrays, they could tune the synaptic interactions between adjacent neurons and program […]
Ultra-thin film of magnetite optimized for spintronics
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, […]
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 […]