Ruddlesden-Popper interface in correlated manganite heterostructures induces magnetic decoupling and dead layer reduction

2016 ◽  
Vol 109 (23) ◽  
pp. 232405 ◽  
Author(s):  
A. Belenchuk ◽  
O. Shapoval ◽  
V. Roddatis ◽  
V. Bruchmann-Bamberg ◽  
K. Samwer ◽  
...  
Keyword(s):  
Dead Layer ◽  
Magnetic Decoupling

Investigation of Dead Layer Thickness in SrRuO3/Ba0.5Sr0.5TiO3/Au Thin Film Capacitors

2000 ◽  
Vol 655 ◽  
Author(s):  
L. J. Sinnamon ◽  
R. M. Bowman ◽  
J. M. Gregg
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Layer Thickness ◽  
Perovskite Phase ◽  
Frequency Dispersion ◽  
Dead Layer ◽  
Parameter Ratio ◽  
Thin Film Capacitors ◽  
Dead Layer Thickness ◽  
The Dead

AbstractThin film capacitors with barium strontium titanate (BST) dielectric layers of 7.5 to 950 nm were fabricated by Pulsed Laser Deposition. XRD and EDX analyses confirmed a strongly oriented BST cubic perovskite phase with the desired cation stoichiometry. Room temperature frequency dispersion (ε100 kHz / ε100 Hz) for all capacitors was greater than 0.75. Absolute values for the dielectric constant were slightly lower than expected. This was attributed to the use of Au top electrodes since the same sample showed up to a threefold increase in dielectric constant when Pt was used in place of Au. Dielectric constant as a function of thicknesses greater than 70 nm, was fitted using the series capacitor model. The large interfacial parameter ratio di / εi of 0.40 ± 0.05 nm implied a significant dead-layer component within the capacitor structure. Modelled consideration of the dielectric behaviour for BST films, whose total thickness was below that of the dead layer, predicted anomalies in the plots of d/ ε against d at the dead layer thickness. For the SRO/BST/Au system studied, no anomaly was observed. Therefore, either (i) 7.5 nm is an upper limit for the total dead layer thickness in this system, or (ii) dielectric collapse is not associated with a distinct interfacial dead layer, and is instead due to a through-film effect.

Measurements of the dead layer in superfluid4He films on H3 and C60

1994 ◽  
Vol 194-196 ◽  
pp. 619-620
Author(s):  
P.W. Adams ◽  
V. Pant ◽  
A.F. Hebard
Keyword(s):  
Dead Layer ◽  
The Dead

scholarly journals Surface Dead Layer for Quasiparticles Near a Mott Transition

2009 ◽  
Vol 102 (6) ◽  
Author(s):  
Giovanni Borghi ◽  
Michele Fabrizio ◽  
Erio Tosatti
Keyword(s):  
Mott Transition ◽  
Dead Layer

scholarly journals Propidium iodide staining underestimates viability of adherent bacterial cells

2018 ◽  
Author(s):  
Merilin Rosenberg ◽  
Nuno F. Azevedo ◽  
Angela Ivask
Keyword(s):  
Dna Binding ◽  
Propidium Iodide ◽  
Laser Scanning Microscopy ◽  
Red Cells ◽  
Extracellular Dna ◽  
Dead Layer ◽  
Confocal Laser ◽  
Adherent Cells ◽  
Bacterial Viability ◽  
Viability Staining

AbstractCombining membrane impermeable DNA-binding stain propidium iodide (PI) with membrane-permeable DNA-binding counterstains is a widely used approach for bacterial viability staining. In this paper we show that PI staining of adherent cells in biofilms may significantly underestimate bacterial viability due to the presence of extracellular nucleic acids. We demonstrate that gram-positive Staphylococcus epidermidis and gram-negative Escherichia coli 24-hour initial biofilms on glass consist of 76 and 96% PI-positive red cells in situ, respectively, even though 68% the cells of either species in these aggregates are metabolically active. Furthermore, 82% of E. coli and 89% S. epidermidis are cultivable after harvesting. Confocal laser scanning microscopy (CLSM) revealed that this false dead layer of red cells is due to a subpopulation of double-stained cells that have green interiors under red coating layer which hints at extracellular DNA (eDNA) being stained outside intact membranes. Therefore, viability staining results of adherent cells should always be validated by an alternative method for estimating viability, preferably by cultivation.

scholarly journals Resurrected from the dead: Full characterization of an old HPGe detector using γ-ray and CT tomographies coupled to standard calibration techniques and simulations

2019 ◽  
Vol 24 ◽  
pp. 174
Author(s):  
V. Angelopoulou ◽  
E. Kouvaris ◽  
V. Lagaki ◽  
T. J. Mertzimekis ◽  
P. Papagiannis
Keyword(s):  
Hpge Detector ◽  
Bulk Sample ◽  
Dead Layer ◽  
Operational Mode ◽  
Ct Scanner ◽  
Environmental Radiation ◽  
Full Characterization ◽  
Technical Specifications ◽  
Γ Ray ◽  
The Dead

A decommissioned co-axial HPGe detector has been recently acquired and returned to operational mode in an effort to build an environmental radiation spectrometer at the University of Athens. The new counting station, GEROS (Germanium for Environmental RadiOactivity Studies), was fully characterized prior to operation to obtain detailed information on its linear response, efficiency and energy resolution. In addition to using point-like calibration sources (60Co,137Cs,152Eu and 226Ra), several bulk sample geometries were calibrated by means of an IAEA standard, focusing on soils, sediments and solid materials. In lieu of deteailed technical specifications, the crystal integrity, especially in regards to the dead layer known to build up over the years was studied by means of γ-ray tomography. The 3D geometry of the crystal was fully reconstructed considering the absorption coefficients, and the dead layer thickness was estimated. The overall crystal alignment inside the case was also checked. The results were verified by placing GEROS inside a medical CT scanner and irradiating it to obtain detailed longitudinal and transverse sections. The results were combined to provide input data for subsequent MCNP5 simulations. Good overall agreement between simulations and measurements was achieved. Despite some expected loss of resolution, the detector was found to perform substantially well.

scholarly journals Simulation of a Breathing Apparatus on Chemically Bound Oxygen with a Circular Pendulum Circuit of the Air Duct Part

2021 ◽  
pp. 46-52
Author(s):  
S.G. Ekhilevskiy ◽  
◽  
O.V. Golubeva ◽  
E.P. Potapenko ◽  
◽  
...  
Keyword(s):  
Maximum Permissible Concentration ◽  
Protective Action ◽  
Dead Layer ◽  
Respiratory Protection ◽  
Sorbent Layer ◽  
Breathing Resistance ◽  
Breathing Apparatus ◽  
Short Period ◽  
The Dead ◽  
Made In

At present, the main prospects for improving the insulating means of respiratory protection are associated with the chemical method of oxygen reservation. The arguments in favor of this choice are the high packing density of oxygen and its self-regulating supply, depending on the physical activity of a person. The main schemes of the air duct part of breathing apparatus on chemically bound oxygen are circular and pendulum. The attempt is made in the article to combine the advantages of the circular (small harmful space) and pendulum (small volume of the dead layer) schemes of breathing apparatus on chemically bound oxygen. For these purposes, the formalism method was developed, which allows mathematically and with the help of a computer to simulate the dynamic sorption activity of the regenerative cartridge of a breathing apparatus with a hybrid (circular-pendulum) scheme of the air duct part. The increase in the protective action of the apparatus is determined due to the use of the resource of the dead sorbent layer in the result of the air flow reverse in the pendulum part of the regenerative cartridge. Feasibility of using a hybrid scheme in the self-rescuers with a short period of protective action is shown. The optimal length of the pendulum part is determined, at which the breathing resistance decreases, and the harmful space occupied by the air returning for inhalation without contact with the unreacted layers of the oxygen-containing product is not increased. Its weak dependence on the total length of the regenerative cartridge and the maximum permissible concentration of carbon dioxide in the air returning to inhalation is shown, which makes the circular pendulum scheme realizable in practice.

Optical Properties of Wurtzite GaN and ZnO Quantum Dots

2004 ◽  
Vol 818 ◽  
Author(s):  
Vladimir A. Fonoberov ◽  
Alexander A. Balandin
Keyword(s):  
Quantum Dots ◽  
Decay Time ◽  
Radiative Decay ◽  
State Energy ◽  
Energy Gap ◽  
Dead Layer ◽  
Bulk Gan ◽  
Piezoelectric Field ◽  
Zno Quantum Dots ◽  
Valence Bands

AbstractWe have investigated exciton states in wurtzite GaN/AlN and ZnO quantum dots. A strong piezoelectric field in GaN/AlN quantum dots is found to tilt conduction and valence bands, thus pushing the electron to the top and the hole to the bottom of the GaN/AlN quantum dot. As a result, the exciton ground state energy in GaN/AlN quantum dots with heights larger than 3 nm exhibits a red shift with respect to bulk GaN energy gap. It is shown that the radiative decay time in GaN/AlN quantum dots is large and increases from 0.3 ns for quantum dots with height 1.5 nm to 1.1×103 ns for the quantum dots with height 4.5 nm. On the contrary, the electron and the hole are not separated in ZnO quantum dots. Moreover, a relatively thick “dead layer” is formed near the surface of ZnO quantum dots. As a result, the radiative decay time in ZnO quantum dots is small and decreases from 73 ps for quantum dots with diameter 1.5 nm to 29 ps for the quantum dots with diameter 6 nm.

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