Search results for "Auxiliary electrode"
showing 10 items of 11 documents
Magnetic tunneling junctions with the Heusler compound
2005
Abstract Certain Heusler phases belong to the materials which are discussed as potential half metals. Here, results of tunneling experiments with the full-Heusler alloy Co 2 Cr 0.6 Fe 0.4 Al are presented. The Heusler alloy is used as an electrode of magnetic tunneling junctions. The junctions are deposited by magnetron DC sputtering using shadow mask techniques with AlO x as a barrier and cobalt as counter electrode. Measurements of the magnetoresistive differential conductivity in a temperature range between 4 and 300 K are shown. An analysis of the barrier properties applying the Simmons model to the bias dependent junction conductivity is performed. VSM measurements were carried out to …
Template electrodeposition and characterization of nanostructured Pb as a negative electrode for lead-acid battery
2019
Abstract Despite Lead Acid Battery (LAB) is the oldest electrochemical energy storage system, diffusion in the emerging sectors of technological interest is inhibited by its drawbacks. The principal ones are low energy density and negative plate sulphating on high rate discharging. In this work, it is shown the possibility of overcoming such drawbacks by using nanostructured lead as a negative electrode. Lead nanowires (NWs) were fabricated by electrochemical deposition in template, which is an easy, cheap, and easily scalable process. Their morphology and crystal structure have been characterized by electron microscopy and X-ray diffraction, respectively. An electrochemical cell simulating…
Recent Advances in Electrochromics for Smart Windows Applications
1998
Electrochromic smart windows are able to vary their throughput of radiant energy by low-voltage electrical pulses. This function is caused by reversible shuttling of electrons and charge balancing ions between an electrochromic thin film and a transparent counter electrode. The ion transport takes place via a solid electrolyte. Charge transport is evoked by a voltage applied between transparent electrical conductors surrounding the electrochromic film/electrolyte/counter electrode stack. This review summarizes recent progress concerning (i) calculated optical properties of crystalline WO3, (ii) electrochromic properties of heavily disordered W oxide and oxyfluoride films produced by reactiv…
Electric current induced modification of germanium nanowire NEM switch contact.
2015
We present an investigation of contact properties of a germanium (Ge) nanowire based nanoelectromechanical (NEM) switch in its ON state. The contact stiffness in the ON state was evaluated by detecting the nanowire's resonance frequency. It was found that the resonance frequency increases when electric current flows through the nanowire/counter electrode contact area. The reason for modification in the contact area is referred to as electric-current-induced processes in the native oxide layer covering the nanowires. The presented resonance shift method is a simple way to indicate strengthening of the nanowire/counter electrode contact area without disassembling the contact.
Oscillatory Changes of the Heterogeneous Reactive Layer Detected with the Motional Resistance during the Galvanostatic Deposition of Copper in Sulfur…
2015
Metallic copper was galvanostatically deposited on quartz|gold resonant electrodes by applying a constant current in a 0.5 M CuSO4/0.1 M H2SO4 aqueous solution. Galvanostatic copper deposition is one of the best methodologies to calibrate the electrochemical quartz crystal microbalances (EQCM), a gravimetric sensor to evaluate changes in mass during the electrochemical reactions through the Sauerbrey equation. The simultaneous measurement of mass, current density, and motional resistance by an EQCM with motional resistance monitoring allows us to characterize the processes occurring on the electrode surface and at the interfacial regions with unprecedented detail. During the galvanostatic c…
Properties of amphiphilic terminally substituted conjugated nonaene- and 2-docosylnonaene carboxylic acids in monolayers at the air-water interface
1991
was a lo-' M Co(NO,), + lo-' M CH,COONa solution, with pH 7.5; the counter electrode was a Pt sheet, conveniently located in the electrochemical cell. After deposition, the electrochemical/electrochromic properties of the films were analyzed in degassed lo-' M KOH electrolyte, in a three electrode cell (Pt wire counter electrode, saturated calomel reference electrode) with optical windows. A PAR 173 potentiostat-galvanostat associated with a PAR 175 function generator was used in the electrochemical experiments. Data were recorded in a analogical X-Y (X-T) recorder. Monochromatic transmission (He-Ne laser, A = 632.8 nm) was recorded in situ, by means of a versatile optical bench; spectral t…
Silver based sensors from CD for chloride ions detection
2021
This preliminary work shows a new and innovative way to produce silver based electrodes from compact discs and its application towards the detection of chloride ions. A complete sensor was obtained from the compact discs with working, reference and counter electrode made of silver. Chloride ions were detected by exploiting the high affinity of silver with this anion to produce silver chloride. This electrochemical oxidation of silver can be monitored by using an electrochemical technique such as linear scan voltammetry. Indeed, during linear scan voltammetry the oxidation of silver to silver chloride lead to a peak current that increases linearly with chloride concentration. Using this tech…
Tunneling junctions of the heavy-fermion superconductor UPd2Al3
1998
Abstract Tunneling spectroscopy on planar Giaever-type junctions is a powerful tool for the investigation of the superconducting state of metals. Since it is possible to prepare high-quality epitaxial thin films of the heavy-fermion compound UPd 2 Al 3 , this method can be used to examine the energy gap of this presumably unconventional superconductor. We prepared cross-junctions consisting of a UPd 2 Al 3 base electrode and a metal counter electrode (Au, Al or Ag). These small area contacts without artificial barriers have only low junction resistances and suffer from irreproducibility. On the other hand, on some of those junctions we observed BCS-like tunneling conductivity. In order to i…
Measuring electrostatic double-layer forces on HOPG at high surface potentials
1999
Abstract The aim of this study was to investigate surface forces in aqueous electrolyte solutions between surfaces with high electric potentials. Therefore the force between a surface of highly oriented pyrolytic graphite (HOPG) and a silicon nitride tip of an atomic force microscope was measured. Various electric potentials by a counter electrode were applied to the HOPG, which served as working electrode. As predicted by the Poisson–Boltzmann theory the electrostatic double-layer force changed only in a narrow potential range of ≈300 mV. At high negative sample potentials, where the negatively charged tip was repelled from the sample, the force saturated. At positive potentials an attract…
Superconducting tunneling spectroscopy on epitaxial UPd2Al3 thin films
1997
Abstract Results of superconducting tunneling spectroscopy experiments performed on two different types of thin film planar junctions of the heavy-fermion compound UPd 2 Al 3 are presented. Cross-type junctions consist of the heavy-fermion base electrode, an insulating layer of native surface oxide and a metal counter electrode (Au or Ag). The contact resistance was only weakly temperature dependent down to the superconducting transition. In the superconducting regime a strongly reduced zero bias conductivity indicated the junction being of the superconductor-insulator-normal metal type. The observed tunneling density of states is clearly due to the superconducting energy gap of UPd 2 Al 3 …