135 research outputs found
Inverse spin Hall effect in Nd doped SrTiO3
Conversion of spin to charge current was observed in SrTiO3 doped with Nd
(Nd:STO), which exhibited a metallic behavior even with low concentration
doping. The obvious variation of DC voltages for Py/Nd:STO, obtained by
inverting the spin diffusion direction, demonstrated that the detected signals
contained the contribution from the inverse spin Hall effect (ISHE) induced by
the spin dependent scattering from Nd impurities with strong spin-orbit
interaction. The DC voltages of the ISHE for Nd:STO were measured at different
microwave frequency and power, which revealed that spin currents were
successfully injected into doped STO layer by spin pumping. The linear relation
between the ISHE resistivity and the resistivity induced by impurities implied
that the skew scattering was the dominant contribution in this case, and the
spin Hall angle was estimated to be 0.17%. This work demonstrated that
extrinsic spin dependent scattering in oxides can be used in spintroics besides
that in heavy elements doped metals
Fingerprinting-based indoor localization using interpolated preprocessed csi phases and bayesian tracking
Indoor positioning using Wi-Fi signals is an economic technique. Its drawback is that multipath propagation distorts these signals, leading to an inaccurate localization. An approach to improve the positioning accuracy consists of using fingerprints based on channel state information (CSI). Following this line, we propose a new positioning method which consists of three stages. In the first stage, which is run during initialization, we build a model for the fingerprints of the environment in which we do localization. This model permits obtaining a precise interpolation of fingerprints at positions where a fingerprint measurement is not available. In the second stage, we use this model to obtain a preliminary position estimate based only on the fingerprint measured at the receiver’s location. Finally, in the third stage, we combine this preliminary estimation with the dynamical model of the receiver’s motion to obtain the final estimation. We compare the localization accuracy of the proposed method with other rival methods in two scenarios, namely, when fingerprints used for localization are similar to those used for initialization, and when they differ due to alterations in the environment. Our experiments show that the proposed method outperforms its rivals in both scenarios.Fil: Wang, Wenxu. Guandong University Of Technology; ChinaFil: Marelli, Damian Edgardo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Rosario. Centro Internacional Franco Argentino de Ciencias de la Información y de Sistemas. Universidad Nacional de Rosario. Centro Internacional Franco Argentino de Ciencias de la Información y de Sistemas; ArgentinaFil: Fu, Minyue. Universidad de Newcastle; Australi
Dynamic indoor localization using maximum likelihood particle filtering
A popular approach for solving the indoor dynamic localization problem based on WiFi measurements consists of using particle filtering. However, a drawback of this approach is that a very large number of particles are needed to achieve accurate results in real environments. The reason for this drawback is that, in this particular application, classical particle filtering wastes many unnecessary particles. To remedy this, we propose a novel particle filtering method which we call maximum likelihood particle filter (MLPF). The essential idea consists of combining the particle prediction and update steps into a single one in which all particles are efficiently used. This drastically reduces the number of particles, leading to numerically feasible algorithms with high accuracy. We provide experimental results, using real data, confirming our claim.Fil: Wang, Wenxu. Guangdong University of Technology; ChinaFil: Marelli, Damian Edgardo. Guangdong University of Technology; China. Centro CientÃfico Nacional e Internacional Francés Argentino de Ciencias de la Información y Sistemas; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Fu, Minyue. Universidad de Newcastle; Australia. Guangdong University of Technology; Chin
Magnetic Mn5Ge3 nanocrystals embedded in crystalline Ge: a magnet/semiconductor hybrid synthesized by ion implantation
The integration of ferromagnetic Mn5Ge3 with the Ge matrix is promising for
spin injection in a silicon-compatible geometry. In this paper, we report the
preparation of magnetic Mn5Ge3 nanocrystals embedded inside the Ge matrix by Mn
ions implantation at elevated temperature. By X-ray diffraction and
transmission electron microscopy, we observe crystalline Mn5Ge3 with variable
size depending on the Mn ion fluence. The electronic structure of Mn in Mn5Ge3
nanocrystals is 3d6 configuration, the same as in bulk Mn5Ge3. A large positive
magnetoresistance has been observed at low temperatures. It can be explained by
the conductivity inhomogeneity in the magnetic/semiconductor hybrid system.Comment: 16 pages, 5 figure
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