Kelvin Functions For Determination Of Magnetic Susceptibility In Nonmagnetic Metals

A method to calculate the real and imaginary parts of the magnetic permeability and susceptibility of nonmagnetic metals by using Kelvin functions is presented. The exact treatment is shown for the massive cylindrical geometry. An expression for a hollow circular cylinder is discussed and expanded to the thin-shell limit.65124505450

Energetics of intrinsic point defects in ZrSiO4_4

Using first principles calculations we have studied the formation energies, electron and hole affinities, and electronic levels of intrinsic point defects in zircon. The atomic structures of charged interstitials, vacancies, Frenkel pairs and anti-site defects are obtained. The limit of high concentration of point defects, relevant for the use of this material in nuclear waste immobilization, was studied with a variable lattice relaxation that can simulate the swelling induced by radiation damage. The limit of low concentration of defects is simulated with larger cells and fixed lattice parameters. Using known band offset values at the interface of zircon with silicon, we analyze the foreseeable effect of the defects on the electronic properties of zircon used as gate in metal-oxide-semiconductor devices.Comment: preprint 16 pages, 4 figures, and 5 table

Surface Polaritons On Large-amplitude Gratings

We present numerical studies of the dispersion relation for surface polaritons that propagate on the surface of a model free-electron metal upon which a periodic grating has been impressed. The calculations are based on the integral equation formulation of the boundary-value problem, as discussed earlier by Toigo, Marvin, Hill, Celli, and others. We employ the "extinction theorem" scheme, which yields convergent results for values of the ratio 0a far in excess of 0.072, where the Rayleigh-Fano method fails when applied to the scattering of a scalar wave from a hard wall with profile given by 0cos(2xa). We give results for the dispersion relation for two grating profiles, the sinusoidal and the symmetric sawtooth forms. © 1981 The American Physical Society.23104965497

Eddy Current Decay Method Applied To A New Geometry

The eddy current decay method for determination of metallic samples resistivities is presented for the case of a hollow circular cylindrical geometry. The theory is developed for two kinds of experimental arrangements: the primary coil is driven by a voltage source or by a current source. The measurements made for several metals (Al, Cu, Nb, brass, and bronze) at room temperature and at the temperature of liquid nitrogen analyzed by the theory give accurate results compared with the four terminal method.61125237524

Photon Emission From Slightly Roughened Tunnel Junctions

In this paper, we derive expressions for the distribution in angle and frequency of electromagnetic radiation emitted from fluctuations in the tunneling current between two metals separated by a thin oxide barrier. The calculation provides an explicit description of the decoupling of the surface polariton from the surface by virture of small-amplitude roughness present there. In addition, we find radiation from direct coupling of current fluctuations in the junction structure to the transverse radiation field. Numerical calculations are presented which explore the predictions of the theory, when applied to structures similar to those studied experimentally by Lambe and McCarthy. We suggest interpretations of some features of their data, and data reported by Adams, Wyss, and Hansma. The theory indicates that as the amplitude of the roughness is increased, the quantum efficiency of the device should saturate to approach a value independent of the roughness amplitude. © 1979 The American Physical Society.20124962498

Reflection Of Magnetoelastic Waves From Ferromagnetic Surfaces

We present theoretical studies of the reflection of bulk magnetoelastic waves from the surface of a ferromagnet, with magnetization parallel to the surface. The calculations show a pronounced left-to-right asymmetry in the amplitude of the reflected wave. The origin of this asymmetry is in the boundary conditions which when applied to surface magnetoelastic waves theory lead to nonreciprocal dispersion relations. The frequency dependence of the reflectivity is studied here, for particular selected geometries which exhibit the left-to-right asymmetry. © 1980 The American Physical Society.2294445444

Density Of States Of A Semi-infinite Rare-earth Metal With Magnetic Structure: A Simple Model

Using a simple tight-binding model and the transfer matrix approach, we have calculated the spectral density of states (SDOS) of a rare-earth metal in the presence of a surface for different magnetic arrangements (such as ferromagnetic, antiferromagnetic, and conical orderings). The local density of states (LDOS) has also been calculated for some examples, integrating the SDOS over the Brillouin zone. The main effect observed deals with the absence of Van Hove's singularities in the surface LDOS, a fact that appears to be an intrinsic property of the surface. Finally the relaxation of the overlap parameters at the surface is discussed and some numerical examples are shown. © 1979 The American Physical Society.2062269227

DENSITY OF STATES OF A SEMI-INFINITE RARE-EARTH-METAL WITH MAGNETIC-STRUCTURE - SIMPLE-MODEL

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Roughness And The Mean Free Path Of Surface Polaritons In Tunnel-junction Structures

We calculate the mean free path of surface polaritons in tunnel junctions, in the presence of roughness on the surface of the outermost film. When these results are combined with our earlier theory of light emission from roughened junctions subject to a dc bias voltage, we discuss the saturation of the intensity of emitted light with increased roughness amplitude. Also, the probability that the surface polariton emits a photon into the vacuum during its lifetime is estimated and found to be very small for waves in the near infrared and visible frequency range. © 1980 The American Physical Society.21115175518

KELVIN FUNCTIONS FOR DETERMINATION OF MAGNETIC-SUSCEPTIBILITY IN NONMAGNETIC METALS

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