Search results for "electronics"
showing 10 items of 4340 documents
SIC based solid state protections switches for space applications
2017
Development and technology maturation of Silicon Carbide (SiC) power transistors over the last 15 years has motivated its study in aerospace systems. When compared with Si devices, superior voltage blocking capacity and the capability of operation at higher temperatures, give important advantages in space power electronics applications, similar to what happens in terrestrial electronics. This paper discusses the use of SiC power transistors for Solid State Power Switches especially addressed to the space segment. Two applications will be covered, the first is the Solid State Shunt Switch, widely used in high power Direct Energy Transfer (DET) photovoltaic power regulators and the second is …
Parasitic Bipolar Action in SiC Power MOSFETs Demonstrated by Two-Photon Laser Experiment
2018
A two-photon absorption technique is explored for Silicon carbide power MOSFETs and power junction barrier Schottky diodes using a pulsed laser. The similarities in design between the specific MOSFETs and diodes tested permit using mechanisms existing in the different structures as explanation for observed current variation with laser position. The diode shows variation in average current with change in laser depth only, whereas the MOSFET shows variation both with shifts in depth and shifts in position across the striped geometry of the device. The variation is explained to be due to bipolar amplification of the charge carriers generated in the MOSFET when a pulse focus includes a channel …
Electrical transport in lead-free (Na0.5Bi0.5)1–xSrxTiO3 ceramics (x = 0, 0.01 and 0.02)
2017
Lead-free (Na0.5Bi0.5)1xSrxTiO3 (x = 0, 0.01 and 0.02) ceramics were manufactured through a solid-state mixed oxide method and their ac (σac) and dc (σdc) electric conductivity were studied. It is ...
Flash annealing influence on structural and electrical properties of TiO2/TiO/Ti periodic multilayers
2014
Abstract Multilayered structures with a 40 nm period composed of titanium and two different titanium oxides, TiO and TiO 2 , were accurately produced by DC magnetron sputtering using the reactive gas pulsing process. These multilayers were sputtered onto Al 2 O 3 sapphire to avoid substrate compound diffusion during flash annealing (ranging from 350 °C to 550 °C). Structure and composition of these periodic TiO 2 /TiO/Ti stacks were investigated by X-ray diffraction, X-ray photoemission spectroscopy and transmission electronic microscopy techniques. Two crystalline phases α-Ti and fcc-TiO were identified in the metallic-rich sub-layers whereas the oxygen-rich ones were composed of a mixture…
The challenge in realizing an exchange coupled BiFeO3-double perovskite bilayer
2020
Abstract In this work we propose a device design for efficient voltage control of magnetism. The magnetization of a ferrimagnetic double perovskite may be manipulated by an exchange coupled layer of multiferroic BiFeO3. Bilayers of Barium doped BiFeO3 and ferrimagnetic double perovskite Sr2FeMoO6 have been prepared by pulsed laser deposition motivated by the possibility of strong interlayer exchange coupling. While single layers of each material show high quality we observe that in both stacking orders the first layer decomposes during the deposition of the second layer. The reason for the decomposition are strongly differing growth conditions for BiFeO3 and Sr2FeMoO6. This means that the g…
Quasi-antiferromagnetic multilayer stacks with 90 degree coupling mediated by thin Fe oxide spacers
2019
We fabricated quasiantiferromagnetic (quasi-AFM) layers with alternating antiparallel magnetization in the neighboring domains via 90° magnetic coupling through an Fe-O layer. We investigated the magnetic properties and the relationship between the magnetic domain size and the 90° magnetic coupling via experiments and calculations. Two types of samples with a Ru buffer and a (Ni80Fe20)Cr40 buffer were prepared, and we found that with the NiFeCr buffer, the sample has a flatter Fe-O layer, leading to stronger 90° magnetic coupling and a smaller domain size compared with the Ru buffer sample. This trend is well explained by the bilinear and biquadratic coupling coefficients, A12 and B12, in L…
Modification of magnetic anisotropy in Ni thin films by poling of (011) PMN-PT piezosubstrates
2016
ABSTRACTThis study reports the magnetic and magnetotransport properties of 20 nm thick polycrystalline Ni films deposited by magnetron sputtering on unpoled piezoelectric (011) [PbMg1/3Nb2/3O3]0.68-[PbTiO3]0.32 (PMN-PT) substrates. The magnetoresistance (MR), as well as the magnetization reversal, is found to depend on the polarization state of the piezosubstrate. Upon poling the PMN-PT substrate, which results in a transfer of strain to the Ni film, the MR value decreases by a factor of 12 at room temperature and a factor of 21 at 50 K for the current direction along the PMN-PT [100] direction, and slightly increases for the [01] current direction. Simultaneously, a strong increase in the …
A quartz amplifier for high-sensitivity Fourier-transform ion-cyclotron-resonance measurements with trapped ions
2019
Single-ion sensitivity is obtained in precision Penning-trap experiments devoted to light (anti)particles or ions with low mass-to-charge ratios, by adding an inductance coil to an amplifier connected to the trap, both operated at 4 K. However, single-ion sensitivity has not been reached on heavy singly or doubly charged ions. In this publication, we present a new system to reach this point, based on the use of a quartz crystal as an inductance, together with a newly developed broad-band (BB) amplifier. We detect the reduced-cyclotron frequency of 40Ca+ ions stored in a 7-tesla open-ring Penning trap. By comparing the detected electric signal obtained with the BB amplifier and the fluoresce…
High temperature oxidation of Mg2(Si-Sn)
2016
Abstract High temperature oxidation of Mg 2 Si 1- x Sn x alloys ( x = 0.1 ⿿ 0.6) has been investigated. The oxidation rate was slow for temperatures below 430 °C. In the temperature range between 430⿿500 °C all the alloys exhibited breakaway oxidation. The onset temperature of the breakaway region in general decreased with increasing level of Sn in the alloy. The breakaway behavior is explained by a combination of the formation of a non-protective MgO layer and the formation of Sn-rich liquid at the interface between the oxide and Mg depleted Mg 2 Sn.
Magneto-optical properties of two-layer film systems based on Fe and Cr
2020
The results of the investigation of two-layer Fe/Cr systems using the magneto-optical Kerr effect (MOKE) are presented in this paper. The samples were obtained by thermal evaporation in a vacuum with a thickness of individual layers from 2 nm to 50 nm. It was found that the presence of the Cr layer significantly affects the values of the coercivity and the Kerr angle. At a substrate temperature of 450 K, the value of the coercivity is almost half that of the same sample obtained at room temperature of the substrate. In addition, the influence of the order of deposition of layers, as well as the effect of a thin gold protective layer on the parameters measured by the Kerr method, is shown. …