Search results for "polarization."
showing 10 items of 1842 documents
Electric-Field Control of Spin-Orbit Torques in Perpendicularly Magnetized W/CoFeB/MgO Films
2020
Controlling magnetism by electric fields offers a highly attractive perspective for designing future generations of energy-efficient information technologies. Here, we demonstrate that the magnitude of current-induced spin-orbit torques in thin perpendicularly magnetized CoFeB films can be tuned and even increased by electric-field generated piezoelectric strain. Using theoretical calculations, we uncover that the subtle interplay of spin-orbit coupling, crystal symmetry, and orbital polarization is at the core of the observed strain dependence of spin-orbit torques. Our results open a path to integrating two energy efficient spin manipulation approaches, the electric-field-induced strain a…
Bulk spin polarization of magnetite from spin-resolved hard x-ray photoelectron spectroscopy
2021
Physical review / B 104(4), 045129 (1-10) (2021). doi:10.1103/PhysRevB.104.045129
Direct observation of polar nanostructures in PLZT ceramics for electrooptic applications
2004
ABSTRACTTransparent Pb1-yLay(Zr1-xTix)1-y/4O3(PLZT, y=0.0975, x=0.35) ceramics prepared via hot pressing techniques were studied via piezoelectric force microscopy (PFM). Clear piezoelectric contrast is observed in a cubic relaxor phase indicating spatial distribution of polarization with an average cluster size of about 50 nm. The irregular polarization pattern is associated with the formation of a glassy state, where random electric and stress fields are responsible for the disruption of the long-range ferroelectric order. Local poling of the ceramics resulted in the formation of a stable micron-size domain that could be continuously switched under varying dc bias (local hysteresis loop).…
Field Induced Evolution of Nanoscale Structures in Relaxor PLZT Ceramics
2005
Abstract The kinetics of the nanoscale structures under application of bipolar and unipolar ac field was investigated by recording of the switching charge in wide temperature and field range in hot-pressed relaxor PLZT ceramics. Original analysis of the switching charge data was based on the consideration of the field induced transformation as an evolution of the nanoscale domain structure with nanoscale nonpolar inclusions. We have shown that the inhomogeneous depolarization field produced by the bound charges existing at the interphase boundaries play the key role in spontaneous backswitching effects.
A Columnar Liquid Crystal with Permanent Polar Order
2015
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Improvement in the performance of low temperature H2-O2 fuel cell with chitosanephosphotungstic acid composite membranes
2016
Abstract Free-standing chitosan/phosphotungstic acid polyelectrolyte membranes, prepared by ionotropic gelation on alumina porous supports, were employed as proton conductor in low temperature H 2 –O 2 fuel cell. A drying step on glass substrate was introduced in the fabrication procedure to reduce shrinkage and consequent corrugation. Membranes were tested with electrodes prepared according to different procedures and with two different Pt loadings, namely 0.5 and 1 mg cm −2 . Both the investigated kinds of electrodes allowed to get very promising power peaks of 550 mW cm −2 in spite of the different Pt content. The polarization curves and the electrochemical impedance spectra suggest that…
Local structure in Ga1−xInxSe alloys
2021
Abstract In this work we study the local structure of layered G a 1 − x I n x S e alloys by means of X-ray Absorption. We complement our research with a Raman study. The available alloys have compositions close to the host binaries. The dependence of XANES (X-ray Near Edge Structure) features with synchrotron polarization clearly establishes the substitutional character of the alloying cations. Interstitial atoms, if present, remain under the detection limit of the technique. EXAFS (Extended X-ray Absorption Fine Structure) demonstrates the existence of G a − I n bonds in the alloys. The cation-anion bond-lengths in the alloys remain similar to that of the pure compounds. There is no signif…
Magnon mode selective spin transport in compensated ferrimagnets
2017
We investigate the generation of magnonic thermal spin currents and their mode selective spin transport across interfaces in insulating, compensated ferrimagnet/normal metal bilayer systems. The spin Seebeck effect signal exhibits a non-monotonic temperature dependence with two sign changes of the detected voltage signals. Using different ferrimagnetic garnets, we demonstrate the universality of the observed complex temperature dependence of the spin Seebeck effect. To understand its origin, we systematically vary the interface between the ferrimagnetic garnet and the metallic layer, and by using different metal layers we establish that interface effects play a dominating role. They do not …
Fabrication of long period fiber gratings of subnanometric bandwidth.
2017
This paper reports on the fabrication of long period fiber gratings having subnanometric bandwidth in the 1500 nm spectral region. Large gratings have been photo-inscribed in a high NA fiber, the grating pitch and the order of the HE cladding mode are optimized to produce gratings with a large number of periods and preventing the coupling to TE, TM or EH modes. Resonances with a FWHM of 0.83 nm and 0.68 nm have been achieved for gratings 15 and 20 cm long respectively, the free spectral range between transmission notches is 125 nm. The polarization effects and the sensitivity of the gratings to temperature and to strain variations are presented as well. © 2015 Optical Society of America Thi…
Electrochemical Fabrication and Physicochemical Characterization of Metal/High-k Insulating Oxide/Polymer/Electrolyte Junctions
2014
Photoelectrochemical polymerization of poly(3,4-ethylenedioxythiophene), PEDOT, was successfully realized on anodic film grown to 50 V on magnetron sputtered Ti-6 atom % Si alloys. Scanning electron microscopy allowed us to evidence formation of compact and uniform polymer layers on the oxide surface. Photoelectrochemical and impedance measurements showed that photopolymerization allows one to grow PEDOT in its conducting state, while a strong cathodic polarization is necessary to bring the polymer in its p-type semiconducting state. Information on the optical and electrical properties of metal/oxide/polymer/electrolyte junctions proves that PEDOT has promising performance as an electrolyte…