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In our numerical study, we identify the best conditions for efficient domain wall motion by spinorbit torques originating from the Spin Hall effect or Rashba effect. We demonstrate that the effect depends critically on the domain wall configuration, the current injection scheme and the symmetry of the spin-orbit torque. The best identified configuration corresponds to a Néel wall driven by spin Hall Effect in a narrow strip with perpendicular magnetic anisotropy. In this case, the domain wall velocity can be a factor of 10 larger than that for the conventional current-inplane spin-transfer torque.PACS : 75.70.Ak-75.60.Ch-75.78.FgThe fundamental concepts of spintronics are based on the generation, manipulation and detection of spin polarized currents. It has led in the last two decades to the development of a new generation of magnetic sensors, and notably read heads of hard disks and of non volatile magnetic memories (MRAM) that are expected to supplant semiconductor based memory devices. In classical spintronics, one generally creates a spin current by passing a charge current through a thin ferromagnetic layer, whose magnetization direction can be controlled by an external applied field or more efficiently by spin transfer torques. Recently an alternative way has emerged to control the magnetization configuration of a ferromagnetic layer that is based on current-induced spin-orbit (SO) torques, namely the Spin Hall Effects [1] and the Rashba effect [2]. Such SO torques are expected for magnetic stripes adjacent to a nonmagnetic conductive layer with strong spin-orbit interactions (SO layer) [3]. The exploitation of these SO effects 1

Spin-transfer torque magnetic random access memory (STT-MRAM) is a novel, magnetic memory technology that leverages the base platform established by an existing 100+nm node memory product called MRAM to enable a scalable nonvolatile memory solution for advanced process nodes. STT-MRAM features fast read and write times, small cell sizes of 6F 2 and potentially even smaller, and compatibility with existing DRAM and SRAM architecture with relatively small associated cost added. STT-MRAM is essentially a magnetic multilayer resistive element cell that is fabricated as an additional metal layer on top of conventional CMOS access transistors. In this review we give an overview of the existing STT-MRAM technologies currently in research and development across the world, as well as some specific discussion of results obtained at Grandis and with our foundry partners. We will show that in-plane STT-MRAM technology, particularly the DMTJ design, is a mature technology that meets all conventional requirements for an STT-MRAM cell to be a nonvolatile solution matching DRAM and/or SRAM drive circuitry. Exciting recent developments in perpendicular STT-MRAM also indicate that this type of STT-MRAM technology may reach maturity faster than expected, allowing even smaller cell size and product introduction at smaller nodes.

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Oxidized and neutral films of polypyrrole have been prepared electrochemically in the absence of oxygen and water. The neutral rms are insulating and can be readily oxidized by chemical oxidizing agents to give films of greater conductivity than can be achieved by electrochemical oxidation. Optical spectroscopy provides evidence for the similarity of the polymeric carbonium ion produced by both types of oxidation. NMR studies are consistent with the-,a' bonding in these polymers; they also show the expected downfield shifts relative to the neutral polymer on both chemical and electrochemical oxidation. ESR studies of both the electrochemically oxidized and the neutral polymer suggest the presence of highly mobile spins. Oxidized and neutral films of polypyrrole have been prepared electrochemically in the absence of oxygen and water. The neutral films are insulating and can be readily oxidized by chemical oxidizing agents to give films of greater conductivity than can be achieved by electrochemical oxidation. Optical spectroscopy provides evidence for the similarity of the polymeric carbonium ion produced by both types of oxidation. NMR studies are consistent with the a,a' bonding in these polymers; they also show the expected downfield shifts relative to the neutral polymer on both chemical and electrochemical oxidation. ESR studies of both the electrochemically oxidized and the neutral polymer suggest the presence of highly mobile spins.