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Manuel Vázquez - One of the best experts on this subject based on the ideXlab platform.
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Stress Dependence of the switching field in glass-coated microwires with positive magnetostriction
Journal of Magnetism and Magnetic Materials, 2012Co-Authors: Rudolf Sabol, R. Varga, P. Vojtanik, J. Hudak, J. Blazek, D. Praslička, G. Badini, Manuel VázquezAbstract:Abstract We have studied the Stress Dependence of the switching field in the glass-coated FeNbSiB microwire. The Stress Dependence can be tailored by properly choosing the frequency of exciting magnetic field. At low frequencies, the switching field is weakly dependent on the mechanical Stress, which is ideal for sensors of magnetic field or temperature. Increasing the frequency leads to the increase of the Stress Dependence of the switching field. The slope of the Stress Dependence is almost linear and the switching field increases its value from 128 A/m at 0 MPa to 242 A/m at 160 MPa.
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Stress Dependence of the Switching Field in Glass Coated Microwires
Acta Physica Polonica A, 2008Co-Authors: E. Komova, M. Varga, R. Varga, P. Vojtanik, Jacob Torrejon, M. Provencio, Manuel VázquezAbstract:Here we present the study of the Stress Dependence of the switching field in amorphous glass-coated magnetic microwire of composition FeNiMoB. Samples were heat treated in the temperature range from 250◦C up to 500◦C in order to obtain relaxed and nanocrystalline state. As-cast microwire shows strong Stress Dependence of the switching field, which decreases with the temperature of annealing. The sample is almost not Stress dependent after heat treatment at 425◦C, because the magnetostriction vanishes. However, the strongest Stress Dependence was found for the microwire annealed at 400◦C, just below the optimal annealing temperature to obtain the nanocrystalline state.
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Stress Dependence of the magnetization process in amorphous wires and ribbons
Journal of Applied Physics, 1995Co-Authors: R. Sato Turtelli, J.p. Sinnecker, R. Grössinger, Manuel VázquezAbstract:Magnetization processes in Fe75Si10B15 and (Co92.5Fe6.3Nb1)77.5Si7.5B15 amorphous wires were studied by measuring the Stress Dependence of the hysteresis loops as well of the pinning field. Disaccommodation measurements were also used to characterize quenched‐in Stresses and to study magnetization processes. The results were compared with those of ribbons with similar compositions. It is shown that the geometry of the samples (wires and ribbons) due to the different cooling conditions determines the different domain structures and consequently the magnetization process.
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Stress Dependence of magnetostriction in amorphous ferromagnets: its variation with temperature and induced anisotropy
Journal of Magnetism and Magnetic Materials, 1992Co-Authors: J. M. González, Manuel Vázquez, J.m. Blanco, Antonio Hernando, J.m. Barandiarán, G. RiveroAbstract:Abstract In this work we report magnetostriction measurements obtained in a Co-rich amorphous alloy in which macroscopic anisotropies of different easy axis directions and strengths were induced. Particular interest was focused on the determination of the thermal evolution of the Stress Dependence of the magnetostriction as well as the influence of the anisotropy on such evolution. Although the results are within the experimental accuracy limit some conclusions have been drawn. In particular, the influence of the easy magnetization direction on the thermal variation of the Stress Dependence at low temperature seems clear from the results we show here. Also we report for the first time the appearance of a decrease in the absolute value of the Stress derivative of the magnetostriction after thermal treatment.
A.c.h. Rowe - One of the best experts on this subject based on the ideXlab platform.
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Mechanical Stress Dependence of the Fermi level pinning on an oxidized silicon surface
Applied Surface Science, 2019Co-Authors: L. Martinelli, F. Cadiz, A. Bendounan, S. Arscott, F. Sirotti, A.c.h. RoweAbstract:A combination of micro-Raman spectroscopy and micro-XPS (X-ray photo-electron spectroscopy) mapping on statically deflected p-type silicon cantilevers is used to study the mechanical Stress Dependence of the Fermi level pinning at an oxidized silicon (001) surface. With uniaxial compressive and tensile Stress applied parallel to the ⟨110⟩ crystal direction, the observations are relevant to the electronic properties of strain-silicon nano-devices with large surface-to-volume ratios such as nanowires and nanomembranes. The surface Fermi level pinning is found to be even in applied Stress, a fact that may be related to the symmetry of the Pb0 silicon/oxide interface defects. For Stresses up to 240 MPa, an increase in the pinning energy of 0.16 meV/MPa is observed for compressive Stress, while for tensile Stress it increases by 0.11 meV/MPa. Using the bulk, valence band deformation potentials the reduction in surface band bending in compression (0.09 meV/MPa) and in tension (0.13 meV/MPa) can be estimated.
David L Kohlstedt - One of the best experts on this subject based on the ideXlab platform.
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the Stress Dependence of olivine creep rate implications for extrapolation of lab data and interpretation of recrystallized grain size
Earth and Planetary Science Letters, 2015Co-Authors: Greg Hirth, David L KohlstedtAbstract:Abstract Based on measured values for the Stress exponent, n ≈ 3.5 , combined with the empirically determined relationship between dislocation density and Stress ( ρ ∝ σ 1.37 ) and an analysis of diffusion kinetics in olivine, we conclude that silicon pipe diffusion limits strain rate in the dislocation creep regime. Furthermore, assuming that steady state recrystallized grain size is set by a dynamic balance between strain energy density (associated with dislocations) and surface energy density (associated with grain boundaries), the resulting Dependence of recrystallized grain size on Stress accurately describes experimental observations when the empirical dislocation density versus Stress relationship is accounted for ( d ∝ 1 / σ 1.37 ). The improved physical understanding of the Stress Dependence of creep rate provides justification for incorporation of experimentally derived flow laws into models of geodynamical process and grain size evolution. These lab constraints combined with independent analyses of the Stress Dependence of mantle viscosity based on geophysical data provide bounds on rheological properties such as the yield Stress of the lithosphere.
Giuseppe Pezzotti - One of the best experts on this subject based on the ideXlab platform.
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Stress Dependence of the Raman spectrum of polycrystalline barium titanate in presence of localized domain texture
Journal of Applied Physics, 2007Co-Authors: Tatsuo Sakashita, Marco Deluca, Hirokazu Chazono, Shinsuke Yamamoto, Giuseppe PezzottiAbstract:The Stress Dependence of the Raman spectrum of polycrystalline barium titanate (BaTiO3, BT) ceramics has been examined with microprobe polarized Raman spectroscopy. The angular Dependence of the Raman spectrum of the tetragonal BT crystal has been theoretically established, enabling us to assess the Stress Dependence of selected spectral modes without the influence of crystallographic domain orientation. Upon considering the frequency shift of selected Raman modes as a function of orientation between the crystallographic axis and the polarization vector of incident and scattered light, a suitable instrumental configuration has been selected, which allowed a direct residual Stress measurement according to a modified piezospectroscopic procedure. The analysis is based on the selection of mixed photostimulated spectral modes in two perpendicular angular orientations.
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Stress Dependence of the polarized Raman spectrum of polycrystalline lead zirconate titanate
Journal of Applied Physics, 2007Co-Authors: Marco Deluca, Tatsuo Sakashita, Wenliang Zhu, Hirokazu Chazono, Giuseppe PezzottiAbstract:The Stress Dependence of the Raman spectrum of a relaxor-based polycrystalline ferroelectric lead zirconate titanate–lead nickel niobate–lead zinc niobate (PZT–PNN–PZN) has been investigated using polarized Raman microprobe spectroscopy. Emphasis has been placed on explicitly working out the second harmonic equations that relate Raman intensities to the angle between the laser polarization direction and selected crystalline axes. Based on these assessments, the effect under polarized light of crystal orientation on the intensity of selected Raman modes has been rationalized and the obtained experimental data interpreted. Raman spectra were collected with both parallel and cross polarization filters and their Dependence on Stress calibrated with loading the PZT–PNN–PZN samples in a four-point flexural jig. The use of polarized light allowed us to clarify the effect of domain orientation on the Raman spectrum of PZT–PNN–PZN and to perform precise calibrations of the Stress Dependence of the A1(TO4) Raman mo...
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Stress Dependence of sapphire cathodoluminescence from optically active oxygen defects as a function of crystallographic orientation.
Journal of Physical Chemistry A, 2007Co-Authors: Maria Chiara Munisso, Wenliang Zhu, And Andrea Leto, Giuseppe PezzottiAbstract:The cathodoluminescence (CL) spectrum of the synthetic sapphire single crystal has been studied with respect to the different crystallographic planes of the crystal in order to describe the tensorial Stress Dependence of the band related to oxygen defects. Experiments provide the link between CL spectral shift and Stress, which is referred to as the piezo-spectroscopic (PS) relationship. Using the biaxial Stress field developed at the tip of cracks generated from the corners of a Vickers indentation, we clearly detected Stress Dependence for the cumulative band arising from the F+-center transition of optically active oxygen vacancies. The matrix of PS coefficients along different crystallographic axes of single-crystal sapphire could be precisely determined. The shallow nature of the electron probe may enable the characterization of surface Stress fields with a spatial resolution that may not be easily available by conventional laser probes. The PS calibration results collected on oxygen-defect bands all...
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Stress Dependence of Raman vibrational bands of PbWO4 single crystals
Physica Status Solidi (a), 2006Co-Authors: Wenliang Zhu, K. S. Wan, Y. L. Huang, Xiqi Feng, Giuseppe PezzottiAbstract:A microscopic piezo-spectroscopic (PS) investigation of the Stress Dependence of the Raman bands of lead tungstate was conducted, which used a ball-on-ring flexure method, aimed at adding controlled biaxial Stresses on thin-plate samples. Spectral shifts varying with applied loads and in-depth positions were observed for a - and c -plane PbWO4 single crystals, confirmed by polarized Raman experiments. Taking account of the laser probe function, theoretical convolutions were performed to determine precisely the PS coefficients, which were determined as Π11 = Π22 = –1.29 ± 0.20 cm–1/GPa and Π33 = –0.87 ± 0.25 cm–1/ GPa for the 902 cm–1Ag species. Accordingly, the residual Stresses generated by mechanical treatments were analysed based on the derived coefficients. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Stress Dependence of the Raman Spectrum of β‐Silicon Nitride
Journal of the American Ceramic Society, 2005Co-Authors: Valter Sergo, Giuseppe Pezzotti, Katagiri, Naoki Muraki, Toshihiko NishidaAbstract:The Stress Dependence of the Raman bands of β-silicon nitride,β-Si3N4, has been investigated. In the Stress range examined (from-200 to +200 MPa), low-frequency shift bands (namely the 183, 205, and 226 cm−1 lines) do not show any frequency change with the Stress, whereas the high-frequency shift bands (862, 925, and 936 cm−1) have been found to have a linear Stress Dependence. The pertinent piezo-spectroscopic coefficients have been determined and are found to depend strongly on the additives used to promote densification presumably being taken into solid solution into the β-Si3N4 phase.
Krzysztof Kułakowski - One of the best experts on this subject based on the ideXlab platform.
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Tensile Stress Dependence of the magnetostatic interaction between Fe-rich wires
Journal of Magnetism and Magnetic Materials, 2005Co-Authors: Przemysław Gawroński, J. M. González, J.m. Blanco, Arcady Zhukov, Krzysztof KułakowskiAbstract:Abstract We study the influence of the applied tensile Stress on the magnetostatic interaction between two amorphous Fe-rich wires. The hysteresis loop is measured for: (i) conventional wires produced by in-rotation-water method, with diameter of 125 μ m , (ii) cold-drawn wires with diameter of 50 μ m . The Stress Dependence of the interaction field is evaluated from the shape of the hysteresis loops, which show characteristic two-step behaviour. These steps mark the values of the switching field of the wires. For the conventional wires the tensile Stress Dependence of the interaction field can be explained as a result of the tensile Stress Dependence of the magnetization. For the cold-drawn wires, the interaction field shows a maximum with the applied Stress. This behaviour is interpreted as a consequence of a local variation of the domain structure at the wire ends. It modifies the stray field, and—as a consequence—the switching field of the neighbouring wire.
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Stress Dependence of bistability in Co-based amorphous wires
Journal of Magnetism and Magnetic Materials, 1996Co-Authors: Krzysztof Kułakowski, Julian González, P. AragonesesAbstract:Abstract Recent results on the thermal treatment and applied Stress Dependence of magnetic bistability of Co72.5Si12.5B15 amorphous wires are discussed in terms of a propagation mechanism of switching. The spatial distribution of the magnetic anisotropy energy is evaluated from experimental data on the switching field. The contributions from the inner core and the outer shell to the remanence magnetization are separated by means of model calculations. The calculated influence of Stress annealing on the remanence magnetization is found to agree qualitatively with new experimental data.
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Stress Dependence of magnetostriction in (Co0.95Fe0.05)70Si12B18 amorphous alloy
Journal of Magnetism and Magnetic Materials, 1995Co-Authors: L. Dominguez, Krzysztof Kułakowski, J.m. Blanco, J. M. GonzálezAbstract:Abstract The influence of the kind of annealing on the parameters of the law of the Stress Dependence of magnetostriction λ S( σ ) in (Co 0.95 Fe 0.05 ) 70 Si 12 B 18 amorphous alloy has been investigated. The annealings were performed using the current annealing technique without and with tensile Stress ( σ ann = 500 MPa). The evolution of such parameters strongly depends on the kind of annealing, which suggests that such variations of λ s are related to the modifications of the atomic local short-order due to the thermal treatment. In particular, we obtain a positive slope of the Stress Dependence of λ S .
