Spin communication over 30 μ\mum long channels of chemical vapor deposited graphene on SiO2_2

We demonstrate a high-yield fabrication of non-local spin valve devices with room-temperature spin lifetimes of up to 3 ns and spin relaxation lengths as long as 9 $\mu$m in platinum-based chemical vapor deposition (Pt-CVD) synthesized single-layer graphene on SiO$_2$/Si substrates. The spin-lifetime systematically presents a marked minimum at the charge neutrality point, as typically observed in pristine exfoliated graphene. However, by studying the carrier density dependence beyond n ~ 5 x 10$^{12}$ cm$^{-2}$, via electrostatic gating, it is found that the spin lifetime reaches a maximum and then starts decreasing, a behavior that is reminiscent of that predicted when the spin-relaxation is driven by spin-orbit interaction. The spin lifetimes and relaxation lengths compare well with state-of-the-art results using exfoliated graphene on SiO$_2$/Si, being a factor two-to-three larger than the best values reported at room temperature using the same substrate. As a result, the spin signal can be readily measured across 30 $\mu$m long graphene channels. These observations indicate that Pt-CVD graphene is a promising material for large-scale spin-based logic-in-memory applications

Construction of an evidence-based integrated morphology cleavage embryo score for implantation potential of embryos scored and transferred on day 2 after oocyte retrieval

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SOT-MRAM 300mm integration for low power and ultrafast embedded memories

We demonstrate for the first time full-scale integration of top-pinned perpendicular MTJ on 300 mm wafer using CMOS-compatible processes for spin-orbit torque (SOT)-MRAM architectures. We show that 62 nm devices with a W-based SOT underlayer have very large endurance (> 5x10^10), sub-ns switching time of 210 ps, and operate with power as low as 300 pJ.Comment: presented at VLSI2018 session C8-

Distribuição longitudinal de Chironomidae (Diptera) abaixo de uma barragem em um rio neotropical

The damming of a river causes dangerous consequences on structure of the environment downstream of the dam, modifying the sediment composition, which impose major adjustments in longitudinal distribution of benthic community. The construction of Engenheiro Sérgio Motta Dam in the Upper Paraná River has caused impacts on the aquatic communities, which are not yet fully known. This work aimed to provide more information about the effects of this impoundment on the structure of Chironomidae larvae assemblage. The analysis of data of physical and chemical variables in relation to biological data of 8 longitudinal sections in the Upper Paraná River showed that composition of Chironomidae larvae of stations near Engenheiro Sérgio Motta Dam differed of the other stations (farther of the Dam) The predominance of coarse sediments at stations upstream and finer sediments further downstream affected the choice of habitat by different morphotypes of Chironomidae and it caused a change in the structure of this assemblage in the longitudinal stretch.O barramento de um rio pode causar graves consequências sobre a natureza do ambiente, abaixo da barragem, modificando a composição do sedimento, as quais impõem importantes ajustes da distribuição longitudinal das comunidades bentônicas. A construção da Usina Hidrelétrica Engenheiro Sérgio Motta no alto rio Paraná, tem causado impactos em várias comunidades aquáticas, que ainda não são totalmente conhecidos. Este trabalho objetivou fornecer mais informações sobre os efeitos desse represamento na assembleia de Chironomidae. A análise das variáveis físicas e químicas em relação aos dados biológicos de oito transectos longitudinais no alto rio Paraná revelou que a composição das larvas de Chironomidae das estações mais próximas à barragem da Usina Engenheiro Sérgio Motta diferiu das demais (estações mais distantes). A predominância de sedimentos mais grosseiros nas estações a montante e sedimentos mais finos mais a jusante afetou a escolha de habitat pelos diferentes morfotipos de Chironomidae, que levou a alteração na estrutura desta assembleia ao longo do trecho amostrado.Fil: Pinha, G. D.. Universidade Estadual de Maringá. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais; Brasil.;Fil: Aviz, D.. Universidade Federal Do Pará; Brasil.;Fil: Lopes Filho, D. R.. Universidade Estadual de Maringá. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais; Brasil.;Fil: Petsch, D. K.. Universidade Estadual de Maringá. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais; Brasil.;Fil: Marchese Garello, Mercedes Rosa. Consejo Nacional de Investigaciones científicas y Técnicas. Centro Científico Tecnológico CONICET- Santa Fe. Instituto Nacional de Limnologia (i); Argentina;Fil: Takeda, A. M.. Universidade Estadual de Maringá; Brasil.

Field-free deterministic ultra fast creation of skyrmions by spin orbit torques

Magnetic skyrmions are currently the most promising option to realize current-driven magnetic shift registers. A variety of concepts to create skyrmions were proposed and demonstrated. However, none of the reported experiments show controlled creation of single skyrmions using integrated designs. Here, we demonstrate that skyrmions can be generated deterministically on subnanosecond timescales in magnetic racetracks at artificial or natural defects using spin orbit torque (SOT) pulses. The mechanism is largely similar to SOT-induced switching of uniformly magnetized elements, but due to the effect of the Dzyaloshinskii-Moriya interaction (DMI), external fields are not required. Our observations provide a simple and reliable means for skyrmion writing that can be readily integrated into racetrack devices

Antiferromagnetic CuMnAs multi-level memory cell with microelectronic compatibility

Antiferromagnets offer a unique combination of properties including the radiation and magnetic field hardness, the absence of stray magnetic fields, and the spin-dynamics frequency scale in terahertz. Recent experiments have demonstrated that relativistic spin-orbit torques can provide the means for an efficient electric control of antiferromagnetic moments. Here we show that elementary-shape memory cells fabricated from a single-layer antiferromagnet CuMnAs deposited on a III–V or Si substrate have deterministic multi-level switching characteristics. They allow for counting and recording thousands of input pulses and responding to pulses of lengths downscaled to hundreds of picoseconds. To demonstrate the compatibility with common microelectronic circuitry, we implemented the antiferromagnetic bit cell in a standard printed circuit board managed and powered at ambient conditions by a computer via a USB interface. Our results open a path towards specialized embedded memory-logic applications and ultra-fast components based on antiferromagnets

Ultra-Fast Perpendicular Spin-Orbit Torque MRAM

© 1965-2012 IEEE. We demonstrate ultra-fast (down to 400 ps) bipolar magnetization switching of a three-terminal perpendicular Ta/FeCoB/MgO/FeCoB magnetic tunnel junction. The critical current density rises significantly as the current pulse shortens below 10 ns, which translates into a minimum in the write energy in the nanosecond range. Our results show that spin-orbit torque-MRAM allows for fast and low-power write operations, which makes it promising for non-volatile cache memory applications

Femtosecond control of electric currents at the interfaces of metallic ferromagnetic heterostructures

The idea to utilize not only the charge but also the spin of electrons in the operation of electronic devices has led to the development of spintronics, causing a revolution in how information is stored and processed. A novel advancement would be to develop ultrafast spintronics using femtosecond laser pulses. Employing terahertz (10$^{12}$ Hz) emission spectroscopy, we demonstrate optical generation of spin-polarized electric currents at the interfaces of metallic ferromagnetic heterostructures at the femtosecond timescale. The direction of the photocurrent is controlled by the helicity of the circularly polarized light. These results open up new opportunities for realizing spintronics in the unprecedented terahertz regime and provide new insights in all-optical control of magnetism.Comment: 3 figures and 2 tables in the main tex

Room temperature chiral magnetic skyrmion in ultrathin magnetic nanostructures

Magnetic skyrmions are chiral spin structures with a whirling configuration. Their topological properties, nanometer size and the fact that they can be moved by small current densities have opened a new paradigm for the manipulation of magnetisation at the nanoscale. To date, chiral skyrmion structures have been experimentally demonstrated only in bulk materials and in epitaxial ultrathin films and under external magnetic field or at low temperature. Here, we report on the observation of stable skyrmions in sputtered ultrathin Pt/Co/MgO nanostructures, at room temperature and zero applied magnetic field. We use high lateral resolution X-ray magnetic circular dichroism microscopy to image their chiral N\'eel internal structure which we explain as due to the large strength of the Dzyaloshinskii-Moriya interaction as revealed by spin wave spectroscopy measurements. Our results are substantiated by micromagnetic simulations and numerical models, which allow the identification of the physical mechanisms governing the size and stability of the skyrmions.Comment: Submitted version. Extended version to appear in Nature Nanotechnolog