Stochastic high-frequency precession of magnetization in layered structures with antiferromagnetic ordering

2004 ◽  
Vol 46 (11) ◽  
pp. 2073-2080
Author(s):  
A. M. Shutyi ◽  
D. I. Sementsov
Keyword(s):  
High Frequency ◽  
Layered Structures ◽  
Antiferromagnetic Ordering

Fundamental properties of surface waves in lossless stratified structures

2010 ◽  
Vol 466 (2120) ◽  
pp. 2447-2469 ◽  
Author(s):  
Guido Valerio ◽  
David R. Jackson ◽  
Alessandro Galli
Keyword(s):  
Surface Waves ◽  
Dispersion Equation ◽  
High Frequency ◽  
Low Frequency ◽  
Layered Structures ◽  
Graphical Solution ◽  
Fundamental Properties ◽  
The Past ◽  
Permittivity And Permeability ◽  
Constitutive Parameters

This paper is focused on dispersive properties of lossless planar layered structures with media having positive constitutive parameters (permittivity and permeability), possibly uniaxially anisotropic. Some of these properties have been derived in the past with reference to specific simple layered structures, and are here established with more general proofs, valid for arbitrary layered structures with positive parameters. As a first step, a simple application of the Smith chart to the relevant dispersion equation is used to prove that evanescent (or plasmonic-type) waves cannot be supported by layers with positive parameters. The main part of the paper is then focused on a generalization of a common graphical solution of the dispersion equation, in order to derive some general properties about the behaviour of the wavenumbers of surface waves as a function of frequency. The wavenumbers normalized with respect to frequency are shown to be always increasing with frequency, and at high frequency they tend to the highest refractive index in the layers. Moreover, two surface waves with the same polarization cannot have the same wavenumber at a given frequency. The low-frequency behaviours are also briefly addressed. The results are derived by means of a suitable application of Foster’s theorem.

DEFECT DETECTION IN MULTI-LAYERED STRUCTURES USING HIGH FREQUENCY GUIDED WAVES

2011 ◽  
Author(s):  
B. Masserey ◽  
E. Kostson ◽  
P. Fromme ◽  
Donald O. Thompson ◽  
Dale E. Chimenti
Keyword(s):  
Defect Detection ◽  
High Frequency ◽  
Guided Waves ◽  
Layered Structures

scholarly journals Investigating the Effect of Dimension Parameters on Sound Transmission Losses in Nomex Honeycomb Sandwich

2020 ◽  
Vol 10 (9) ◽  
pp. 3109 ◽  
Author(s):  
Da Wang ◽  
Suchao Xie ◽  
Zhejun Feng ◽  
Xiang Liu ◽  
Yingli Li
Keyword(s):  
High Frequency ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Layered Structures ◽  
Test Method ◽  
Core Material ◽  
Impedance Tube ◽  
Tube Test ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb

In this study, an impedance tube test was performed to explore the influence of various dimension parameters of Nomex honeycomb sandwich core material on sound transmission loss (STL). The parameters investigated included the size of the honeycomb cells and thickness of the face sheets and honeycomb cores, and the effects of single- and double-layered sandwich structures were also explored. The boundary element and finite element methods were used to simulate test results. The results show that the size of the honeycomb cells has an insignificant effect on STL. Increasing the thickness of face sheets can move the STL valley point of the material at high frequency (around 5 kHz) in the low-frequency direction and increase the STL in parts of the high frequency band. Increasing the thickness of the honeycomb core can improve STL, on the whole, but the magnitude of the improvement effect becomes weakened after the thickness of the core reaches 30 mm. The STL of double-layered structures was found to be superior to that of the single-layered structures. The simulations reveal that the trends in the STL curves of the honeycomb sandwich panels are influenced by the structural mode of the panels, and are related to the resonance of the materials. The results and relevant conclusions obtained through the above research verify that the law of influence of the structure dimension parameters on the STL measured by the impedance tube is similar to that of the large panel. This can provide a reference for the application of the impedance tube test method in structural noise reduction design.

Ternary aurides RE4Mg3Au10 (RE = La, Ce, Pr) and RE4Cd3Au10 (RE = Y, La–Nd, Sm, Gd–Dy) – ordering variants of the Zr7Ni10 type

2015 ◽  
Vol 70 (12) ◽  
pp. 889-896 ◽  
Author(s):  
Michael Johnscher ◽  
Theresa Block ◽  
Oliver Niehaus ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Susceptibility ◽  
Specific Heat ◽  
Coordination Number ◽  
High Frequency ◽  
Two Dimensional ◽  
Muffle Furnace ◽  
Temperature Dependent ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Gold Compounds

AbstractThe intermetallic gold compounds RE4Mg3Au10 (RE = La, Ce, Pr) and RE4Cd3Au10 (RE = Y, La–Nd, Sm, Gd–Dy) were obtained from the elements through high-frequency melting in sealed niobium tubes and subsequent annealing in a muffle furnace. The new aurides crystallize with the Ca4In3Au10-type structure. They were characterized through Guinier powder patterns. The structures of Pr4.46Cd2.54Au10 and Tb4.38Cd2.62Au10 were refined from single crystal X-ray diffractometer data: Cmce, a = 1396.73(6), b = 1009.38(3), c = 1019.51(3) pm, wR2 = 0.0423, 1281 F2 values, 47 variables for Pr4.46Cd2.54Au10 and a = 1362.68(3), b = 995.52(4), c = 1003.79(3) pm, wR2 = 0.0381, 1594 F2 values, F2 47 variables for Tb4.38Cd2.62Au10. The 8e sites of both crystals show substantial Cd/Pr respectively Cd/Tb mixing, indicating small homogeneity ranges for all RE4+xMg3–xAu10 and RE4+xCd3–xAu10 aurides. The gold atoms in these aurides form a pronounced two-dimensional substructure (275–327 pm Au–Au in Pr4.46Cd2.54Au10) which encages the Mg1/Cd1 (coordination number 8) and RE2 (coordination number 11) atoms. These blocks are separated by the Mg2/Cd2 and RE1 atoms with an intergrowth of Mg2/Cd2@Au8 and RE1@Au10 polyhedra. Temperature dependent magnetic susceptibility and specific heat measurements of Tb4Cd3Au10 have shown antiferromagnetic ordering at a Néel temperature of 12(1) K.

High-frequency signal processing using magnetic layered structures

2009 ◽  
Vol 321 (14) ◽  
pp. 2048-2054 ◽  
Author(s):  
R.E. Camley ◽  
Z. Celinski ◽  
T. Fal ◽  
A.V. Glushchenko ◽  
A.J. Hutchison ◽  
...  
Keyword(s):  
Signal Processing ◽  
High Frequency ◽  
Layered Structures ◽  
Frequency Signal ◽  
High Frequency Signal

scholarly journals High Frequency Guided Waves for Disbond Detection in Multi-Layered Structures

2017 ◽  
Vol 103 (6) ◽  
pp. 932-940 ◽  
Author(s):  
Paul Fromme ◽  
Jean-Pascal Reymondin ◽  
Bernard Masserey
Keyword(s):  
High Frequency ◽  
Guided Waves ◽  
Layered Structures ◽  
Disbond Detection

The Microstructure of Steatite (Protoenstatite)

1985 ◽  
Vol 43 ◽  
pp. 236-237
Author(s):  
W. E. Lee ◽  
A. H. Heuer
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Magnesium Silicate ◽  
Beam Current ◽  
Glassy Matrix ◽  
Angle Of Incidence ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Argon Ions ◽  
High Temperature Polymorph

IntroductionTraditional steatite ceramics, made by firing (vitrifying) hydrous magnesium silicate, have long been used as insulators for high frequency applications due to their excellent mechanical and electrical properties. Early x-ray and optical analysis of steatites showed that they were composed largely of protoenstatite (MgSiO3) in a glassy matrix. Recent studies of enstatite-containing glass ceramics have revived interest in the polymorphism of enstatite. Three polymorphs exist, two with orthorhombic and one with monoclinic symmetry (ortho, proto and clino enstatite, respectively). Steatite ceramics are of particular interest a they contain the normally unstable high-temperature polymorph, protoenstatite.Experimental3mm diameter discs cut from steatite rods (∼10” long and 0.5” dia.) were ground, polished, dimpled, and ion-thinned to electron transparency using 6KV Argon ions at a beam current of 1 x 10-3 A and a 12° angle of incidence. The discs were coated with carbon prior to TEM examination to minimize charging effects.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

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