Results 1 - 10 of 2680
Results 1 - 10 of 2680. Search took: 0.024 seconds
|Sort by: date | relevance|
[en] The set process in a unipolar resistance switching Pt/NiO/Pt thin film was conducted in two different ways: the current-biased set process (current sweep mode) and the voltage-biased set process (voltage sweep mode). In the current-biased set process, a compliance current setting was not necessary for continuing stable resistance switching. The resistance of the low resistance state, the reset and the set switching parameters were compared in both modes of the set processes. The distributions of the set parameters were found to be effectively reduced in the current-biased set process. These intriguing properties can be attributed to the prevention of an overshoot current during the set transition.
[en] We present muon spin relaxation measurements performed on crystals of the heavy fermion superconductor UPt3. In zero applied field, contrary to a previous report, we do not observe an increase of the internal magnetic field in the lower superconducting phase (the B phase). Our result gives an experimental upper bound of the magnetic field that could be associated with the superconducting state. (orig.)
[en] Pt nanoparticles dispersed on ceramic powder such as alumina and ceria powder are used as catalyst materials to reduce pollution from automobile exhaust, power plant exhaust, etc. Much effort has been put to investigate the relationship between types of catalyst support materials and reactivity of the supported metallic particles. The surface shape of support materials can also be expected to control the catalysts size with the surface shape of support materials. In this presentation, we show our SANS (small angle neutron scattering) -USANS (ultra small angle neutron scattering) analysis on the structural differences of different shapes of the same γ alumina powder with different loadings of Pt nanoparticles. Then, the reactivity of the prepared catalyst materials are presented and discussed based on the investigation of the structure of the support materials by SANS. The shapes of gamma alumina, rod-like or plate-like shape, were determined from nanometer to micrometer with USANS and SANS analysis. We found that the platelet-like alumina consists of an aggregate of 2 - 3 layers, which further reduce specific surface area and catalytic activity compared to rod-like shape. Rod-like shape shows more than 100% enhancement in the catalytic activities in model three-way-catalyst (TWC) reactions of CO, NO, and C_3H_6 at low temperature around 200 .deg. C
[en] Thermal stability of submicron scale Co90Pt10 island has been investigated using relief-structured giant magnetoresistive samples. Elongated islands with the lateral dimension of 0.5 μmx2.0 μm and the thickness of 6 nm show nonlinear increase of the coercive field with decreasing temperature. The evaluated energy barrier becomes larger than 80kBT for the thickness ranging from 6 to 18 nm
[en] The flux dynamics at low magnetic fields in UPt3 shows a clear distinction between the relaxation of bulk vortices and those close to the surface. In addition, in the high-temperature A-phase, vortices trapped in the bulk of the specimen after cycling it in a magnetic field creep out as expected, while bulk vortices in the B-phase remain strongly pinned, indicating that an intrinsic, novel pinning mechanism exists in the low-temperature superconducting phase of UPt3. (orig.)
[en] CoPt equiatomic alloy orders according to the tetragonal L10 structure which favors strong magnetic anisotropy. Conversely, magnetism can influence the chemical ordering. We present here ab initio calculations of the stability of the L10 and L12 structures of Co-Pt alloys in their paramagnetic and ferromagnetic states. They show that magnetism strongly reinforces the ordering tendencies in this system. A simple tight-binding analysis allows us to account for this behavior in terms of some pertinent parameters.
[en] Self-organised magnetic arrays (SOMA) of high anisotropy particles are a promising candidate for ultra-high-density recording media. In principle SOMA media have the capability of storing 1 bit per particle, leading to possible reecording densities in excess of 10 Tbit/sq in. In this paper we consider two major aspects of SOMA media, namely the self-organisation process itself and the physics of the particle orientation process