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71.
72.
Tunnel magnetoresistance in alumina, magnesia and composite tunnel barrier magnetic tunnel junctions
Oliver SchebaumVolker Drewello Alexander AugeGünter Reiss Markus MünzenbergHenning Schuhmann Michael SeibtAndy Thomas 《Journal of magnetism and magnetic materials》2011,323(11):1525-1528
Using magnetron sputtering, we have prepared Co-Fe-B/tunnel barrier/Co-Fe-B magnetic tunnel junctions with tunnel barriers consisting of alumina, magnesia, and magnesia-alumina bilayer systems. The highest tunnel magnetoresistance ratios we found were 73% for alumina and 323% for magnesia-based tunnel junctions. Additionally, tunnel junctions with a unified layer stack were prepared for the three different barriers. In these systems, the tunnel magnetoresistance ratios at optimum annealing temperatures were found to be 65% for alumina, 173% for magnesia, and 78% for the composite tunnel barriers. The similar tunnel magnetoresistance ratios of the tunnel junctions containing alumina provide evidence that coherent tunneling is suppressed by the alumina layer in the composite tunnel barrier. 相似文献
73.
S.G. ChigarevE.M. Epshtein P.E. Zilberman 《Journal of magnetism and magnetic materials》2011,323(1):130-132
A tunnel magnetic junction is considered with magnetic hard and magnetic soft layers of cubic symmetry. The magnetic switching of the layers is analyzed for a magnetic field perpendicular to the initial magnetizations. In such a situation, an additional peak in the tunnel magnetoresistance ratio appears at the magnetic field value that is substantially lower than the anisotropy field of the soft layer. 相似文献
74.
Spatial‐skin effect for eigenvibrations of a thick cascade junction with ‘heavy’ concentrated masses
A spectral problem for the Laplace operator in a thick cascade junction with concentrated masses is considered. This cascade junction consists of the junction's body and a great number of ?‐alternating thin rods belonging to two classes. One class consists of rods of finite length, and the second one consists of rods of small length of order . The density of the junction is of order on the rods from the second class and outside of them. The asymptotic behavior of eigenvalues and eigenfunctions of this problem is studied as ? → 0. There exist five qualitatively different cases in the asymptotic behavior of eigenmagnitudes as ? → 0, namely the case of ‘light’ concentrated (α ∈ (0,1)), ‘middle’ concentrated (α = 1), and ‘heavy’ concentrated masses (α ∈ (1, + ∞ )) that we divide into ‘slightly heavy’ concentrated (α ∈ (1,2)), ‘intermediate heavy’ concentrated (α = 2), and ‘very heavy’ concentrated masses (α > 2). In the paper, we study in detail the influence of the concentrated masses on the asymptotic behavior if α ∈ (1,2). We construct the leading terms of asymptotic expansions both for the eigenvalues and eigenfunctions and prove the corresponding asymptotic estimates. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
75.
T. Kawaguchi 《Physica C: Superconductivity and its Applications》2010,470(20):1133-1136
Directed transport of vortices in a Josephson junction network (JJN) with structural disorder is studied using a numerical simulation. Using spatiotemporal modulation of driving currents, the directed transport of vortices occurs even in the presence of disorder under certain conditions. From the analyses of the current–voltage and local voltage characteristics, it is found that the collective motion of vortices has an importance for the occurrence of directed transport. 相似文献
76.
77.
Stefan Rysy Horst Sadowski Reinhard Helbig 《Journal of Solid State Electrochemistry》1999,3(7-8):437-445
Both n- and p-type SiC of different doping levels were electrochemically etched by HF. The etch rate (up to 1.5 μm/min) and
the surface morphology of p-type 6H-SiC were sensitive to the applied voltage and the HF concentration. The electrochemical
valence of 6.3 ± 0.5 elementary charge per SiC molecule was determined. At p-n junctions (p-type layer on a n-type 6H-SiC
substrate) a selective etching of the p-type epilayer could be achieved. For a planar 6H-4H polytype junction (n-type, both
polytypes with equal doping concentrations) the 4H region was selectively etched under UV illumination. Thus polytype junctions
could be marked by electrochemical etching. With HCl instead of HF no etching of SiC occurs, but a SiO2 layer (thickness up to 8 μm) is formed by anodic oxidation.
Received: 29 October 1998 / Accepted: 27 January 1999 相似文献
78.
A detailed quantitative analysis of particle events observed in Charge Coupled Devices (CCDs) requires the knowledge of particle detection properties of the employed CCDs such as the detection threshold for energy deposition, efficiency for different kinds of radiation and the relation between the signal and the deposited energy inside the sensitive volume. For this purpose the CCD-chip was described by a simple geometrical model containing the effective thicknesses of the p-n semiconductor junctions dj and a covering dead layer dT above them as parameters. The corresponding geometrical quantities were experimentally estimated to be 1.3 μm and 0.9 μm respectively by using different kinds of radiation. 相似文献
79.
80.
M. Jaworski 《Theoretical and Mathematical Physics》2005,144(2):1176-1180
We investigate the dynamical properties of an exponentially tapered Josephson junction using a simple one-dimensional model
described by a perturbed (nearly integrable) sine-Gordon equation. An approximate analytic solution is based on the linearization
about a rapidly oscillating background. We compare the analytic results with direct numerical simulations for the magnetic
field patterns in the junction.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 144, No. 2, pp. 348–353, August, 2005 相似文献