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Journal of Applied Physics

Issue 1 • Date Jan 1977

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Displaying Results 1 - 25 of 94
  • Issue Table of Contents

    Page(s): toc1
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    Freely Available from IEEE
  • Polarization and dielectric constant of SrTiO3 glass ceramics at low temperatures

    Page(s): 1 - 4
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    Peaks observed in the temperature dependence of the dielectric constant of SrTiO3 glass ceramics do not appear in the dc polarization. A remanent polarization is observed between 4 and 77 K. The dielectric properties at low temperature are attributed to the relaxation of permanent dipoles to an electret state rather than to antiferroelectric ordering. View full abstract»

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  • Observation of antiferromagnetic domains in nickel oxide by neutron diffraction topography

    Page(s): 5 - 8
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    The antiferromagnetic T‐domain structure of a single‐crystal plate of NiO was investigated by neutron diffraction topography. Two modes of observation were used. Topographs made using nuclear reflections provide images of the domain walls because of the change in lattice distortion associated with the antiferromagnetic ordering via exchange striction; the (non)visibility of walls depends on the Bragg reflection used, and is in good agreement with calculations. On topographs made using magnetic reflections, only one type of domain is imaged at a time, yielding unambiguous identification of the magnetic arrangement in each domain. View full abstract»

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  • Role of integrated lateral stress in surface deformation of He‐implanted surfaces

    Page(s): 9 - 17
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    The first measurements of integrated lateral stress S have been obtained for He implantations to fluences where surface deformation occurs. Implants into Mo, Nb, and Al were carried out at room temperature. The low‐fluence results provide values for the induced volume expansion per implanted He atom. The high‐fluence results demonstrate that blistering, as observed in Mo and Nb, is directly related to relief of S. However, flaking, as observed in Al, does not result in appreciable relief of S. The saturation value of integrated lateral stress, Smax, is proportional to yield stress for the three materials and is independent of the He projected range. A model to describe the blistering phenomenon is developed based on the standard elastic stability equation for a plate subjected to in‐plane forces. This elastic instability model uses only measurable material parameters and does not depend explicitly on the behavior of He in the material. The model explains the τ∝d2/3 relation observed for blister diameter d and thickness τ, and predicts the d‐vs‐τ relation for Nb, Ti, V, Pd, 4301 SS, and Be to within 40% of the values measured by other workers over 3 orders of magnitude variation in d. Comparison of the model with the present Mo and Nb results, where Smax is measured directly, gives agreement to better than 10% with no adjustable parameter. View full abstract»

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  • Annealing characteristics of highly P+‐ion‐implanted silicon crystal—two‐step anneal

    Page(s): 18 - 21
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    Single‐step and double‐step annealing behavior of highly P+‐ion‐implanted layers was investigated by means of four‐point probe measurements, x‐ray double‐crystal spectrometry, and electron diffraction patterns. The x‐ray double‐crystal spectrometry data indicated that, in the case of single‐step annealing, the layer implanted with doses lower than 3×1015/cm2 ions was recovered with the increase of annealing temperature, while the sample implanted with doses of 1×1016/cm2 ions showed the opposite behavior. That is, the latter sample showed a very bad recrystallized layer with polycrystalline regions when it was annealed at temperatures higher than 1000 °C. However, in the case of double‐step annealing, the higher‐temperature annealing process, conducted after long 560 °C annealing, made it possible to obtain a good recrystallized layer, compared with the single‐step annealing case. These results were confirmed by electron diffraction patterns. View full abstract»

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  • Dielectric, elastic, and electro‐optic properties of a liquid crystalline molecular complex

    Page(s): 22 - 24
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    The dielectric and elastic constants as well as the electro‐optic response times of twisted nematic cells of the binary liquid crystalline system N‐ (p‐methoxybenzylidene) ‐p‐n‐butylaniline (MBBA)/4‐cyano‐4′‐pentylbiphenyl (CPB) were studied. The formation of a molecular complex between MBBA and CPB leads to wide mesomorphic ranges and higher dielectric anisotropies, as well as favorable rise and decay times. This latter effect is mainly due to relative decreases in viscosity at a given temperature associated with elevation of the nematic‐isotropic transition temperature. View full abstract»

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  • Bounds on the energy and mean square fields in a heterogeneous dielectric

    Page(s): 25 - 27
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    A variety of upper and lower bounds are obtained on the energy and the mean square electric field and electric displacement in a heterogeneous dielectric subject to arbitrary Dirichlet or Neumann boundary conditions. View full abstract»

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  • Grain‐boundary electromigration in thin films. I. Low‐temperature theory

    Page(s): 28 - 35
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    A Macroscopic mathematical theory is presented accounting for grain‐boundary diffusion and electromigration in the presence of a simultaneous flux of atoms into the surrounding bulk lattice. The model employs a semi‐infinite bicrystal geomettry with a constant source at the origin, and both integral and numerical solutions to the subsequent non‐steady‐state transport equations are given. ONly the case where V2/4Db‐DL2≳0, which is ttrue at low temperatures, is considered in detail. (V, Db, and aδ are the grain‐boundary ion drift velocity, diffusivity, and width, respectively, while DL is the lattice diffusivity.). It is predicted that the time dependence of the displacement of a front of fixed concentration is linear only at short times and parabolic at longer times or with increasing amounts of atoms leakage into the bulk. In addition, the concentration profiles are predicted to have a plateau which becomes less apparent at higher temperatures. A comparison between the present theory and a previous treatment based on an extension of the Fisch analysis will be made. Application to recent results in thin films will be discussed. View full abstract»

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  • Grain‐boundary electromigration in thin films II. Tracer measurements in pure Au

    Page(s): 36 - 45
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    The first direct measurement of the grain‐boundary ion drift velocity in thin Au films over the temperature range 120–250 °C is reported. Central regions on the narrow stripe conductors were selectively embedded with 195Au tracer atoms and the extent of the subsequent transport was evaluated by a high‐resolution autoradiography technique employing the scanning electron microscope. In one operating mode, the secondary electron image of the exposed Ag grains in the photographic emulsion was revealed. The second mode of operation involved detection of fluorescent Ag‐Lα x rays, generated upon impingement of the finely focused electron beam on the Ag grains. The resultant spatial dependence of the x‐ray intensity was ultimately converted into tracer activity profiles. It was found (1) that Ion transport in grain boundaries of Au is anode directed (this is the case whether or not a Mo glue layer is present), (2) that the ion drift velocity in grain boundaries can be expressed as V=[(5.7±0.6) ×10-2j/T] exp [-(0.80±0.03 eV)/kT] (cm/sec), with j given in units of A/cm2, (3) that the effective valence of ions migrating in grain boundaries ranged from -89 at 120 °C to -20 at 250 °C (for a diffusion correlation factor of unity), and (4) that a plateau was observed in the low temperature (≪180 °C) profiles. (At higher temperatures, the plateau was less apparent and the integrated intensity was higher). This last result is in semiquantitative agreement with the theory developed by the authors to account for grain‐boundary diffusion and electromigration, in the presence of simultaneous atom leakage into the lattice. View full abstract»

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  • Oxidation induced stacking faults in n‐ and p‐type (100) silicon

    Page(s): 46 - 51
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    The formation of stacking faults during thermal oxidation of silicon has been investigated. The length and the density of stacking faults, in both n‐ and p‐type 5‐cm‐diam (100) silicon wafers obtained from various manufacturers, were determined as a function of time and temperature of oxidation in dry and steam ambients. There appeared to be two categories of stacking faults. In the first category, the length of the stacking fault was given by L= (const) tn exp(-Q/kT), where n and Q are, respectively, 0.85 and 2.55 eV for dry oxidation and 0.66 and 2.37 eV for steam oxidation. This length was independent of the type (p or n) of the wafer. In the second category, the length of the stacking faults varied randomly across the wafer surface. The number of such faults was only about 5% of the total. For a given oxidation condition, the density of the stacking faults was an order of magnitude or more higher in n‐type wafers than that in p‐type wafers. Except for the very short periods of oxidation (≪20 min) the density was found to be nearly independent of time or temperature of oxidation. View full abstract»

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  • Rotation sensing through electromagnetic‐surface‐acoustic‐wave transduction

    Page(s): 52 - 58
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    Rotation rates ranging from two rotations per day to one rpm have been measured by a novel but simple rotation sensor; rotary position can also be measured. This device utilizes a surface‐acoustic‐wave (SAW) standing‐wave pattern on the circumferential surface of a rotating cylinder. The standing‐wave nodes and antinodes are stationary in the rotating cylinder frame as they move past a separate sensing transducer. Electromagnetic transducers are used for the contactless transduction of SAW’s. The device sensitivity is effectively several orders of magnitude greater than for earlier SAW sensor designs. In addition, we foresee measurements of rotation rates of up to thousands of rpm and down to less than 0.1°/h. Design considerations and alternate sensor designs are discussed. View full abstract»

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  • Persistence of a surface film on a liquid in the presence of disturbance propagation

    Page(s): 59 - 66
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    An impermeable film (such as oil) can be used to prevent gas entrainment by the free surface of a liquid. This film, lying on the liquid, is modeled as a continuous viscoelastic two‐dimensional medium. Cohesion and sufficient thickness of this medium are necessary to ensure effective protection. The authors study the evolution of the system in the case of a progressive surface wave of low amplitude. A theory of linearized disturbances is used to obtain the propagation equation of the wave. The solution of this equation gives the film thickness and the surface tension during the movement and leads to determination of the protection conditions of the liquid. View full abstract»

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  • Zn‐ion‐implantation profiles in CuInSe2 by Auger electron spectroscopy

    Page(s): 67 - 72
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    The depth distribution of implanted Zn in CuInSe2 was investigated using Auger electron spectroscopy coupled with continuous surface layer removal by argon‐ion sputtering. The distribution was found to be influenced by the dose rate used in the implantation. The distribution obtained at a current density of 0.16 μA/cm2 is composed of two parts; one having a nearly Gaussian shape in the leading edge and the other having a nearly exponential shape in the trailing edge after the peak concentration. The tail appears to be due to a rapid diffusion process such as interstitial diffusion. A strong diffusion to the surface was observed from the samples implanted with a current density of 2 μA/cm2. This out‐diffusion may occur through the damaged region as it has a lower activation energy. View full abstract»

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  • Spontaneous emf associated with shape memory effect in TiNi

    Page(s): 73 - 74
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    A transient emf of approximately 0.1 mV lasting for about 100 msec is observed at the ends of a cold‐stressed TiNi wire when a central portion of the wire is rapidly heated to above its shape memory transition temperature. A pulse of opposite polarity is observed during cooling through the transition temperature when the temperature change is coincident with a shape change. The polarity of the voltage is inverted when the electrical leads are reversed, implying that the wire is itself polarized. The observed emf is enhanced in a wire which has been ’’trained’’ so that it displays a double memory. View full abstract»

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  • Effect of hydrogen on the temperature dependence of the elastic constants of tantalum single crystals

    Page(s): 75 - 81
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    An investigation was undertaken to determine whether or not a significant Snoek relaxation mechanism exists when hydrogen is dissolved in tantalum. The experimental approach involved the determination of the changes in the absolute values and the temperature (in the range 136–298 °K) dependence of the elastic constants of single crystals charged with varying amounts of hydrogen up to 10.3 at %. Changes in the absolute values of the elastic constants, as a function of hydrogen concentration, were found to be linear, with positive slopes for C11, CL, and C44, and a negative slope for C′. The small negative slope of C′ yields the distortion parameter (λ12) value of 0.0274. The bulk modulus and the Voight average Young’s modulus were found to increase when hydrogen was introduced into the crystal lattice. The elastic constants exhibit no change in their temperature dependence when either the temperature (in the range 245–298 °K) or the hydrogen concentration (in the range 0–10.3 at.%) was varied. It is concluded that a Snoek relaxation attributed to tetrahedral symmetry of the locally distorted tantalum cubic lattice by hydrogen is insignificant. View full abstract»

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  • Surface‐wave harmonic generation on y‐z, x‐z, and 41 1/2‐x lithium niobate

    Page(s): 82 - 85
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    Optical probing was used to evaluate the coefficient for surface‐wave harmonic generation on three high‐coupling cuts of lithium niobate, namely, y‐z, x‐z, and 41 1/2‐x. Surface‐wave attenuation and acoustic beam diffraction profiles of the fundamental and second harmonic were also measured. View full abstract»

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  • Work function and secondary emission studies of various Cu crystal faces

    Page(s): 86 - 93
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    The work function and its temperature dependence has been measured for the 〈100〉, 〈110〉, 〈111〉, 〈112〉 as well as 13 other Cu crystal planes. The results, obtained with two types of incident electron beam techniques in this experiment, are in good agreement with recent photoelectric and contact potential difference results reported on ion‐sputter‐cleaned surfaces. Variation in secondary emission for different crystal faces was found to be determined primarily by the work function changes of the different crystals and not so much by the bulk lattice orientation. It was also observed that the secondary electrons are not as dependent on the velocity constraints imposed by the Bragg condition as are the electrons having thermal energies. View full abstract»

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  • Cataphoretic distributions of Co, Ni, and Mn in metal‐halide–He discharges

    Page(s): 94 - 98
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    Longitudinal emission intensity measurements for the metals Co, Ni, and Mn in the gas phase in a positive column He discharge tube, where the source of the metal is the corresponding metal chloride contained in a conventional appendage reservoir, have been made. The conditions of the discharge were similar to those of a typical metal vapor laser and concentrations of these nonvolatile metals achieved which are comparable to the positive column lasers. The longitudinal dependence of the Cl+ and various metal atom concentrations illustrates that they are strongly bound together by chemical recombination occurring on the wall of the bore. The failure of such a system to maintain Cu in any appreciable concentration illustrates its limits of applicability, but investigations of laser action in numerous new metal vapor systems should be possible. View full abstract»

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  • X‐ray measurements of electron temperatures in CO2‐laser‐heated magnetoplasmas

    Page(s): 99 - 103
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    Electron temperatures of CO2‐laser‐heated magnetoplasmas were found from differential measurements of soft x‐ray continuum through gaseous absorbers. We observed in argon and helium‐argon plasmas that Te increases with longitudinal magnetic field and is a strongly peaked function of the pressure of the target gas. Plasma dynamics are strongly influenced by the presence of at least eight‐times‐ionized argon. View full abstract»

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  • Arc durations as a function of contact metal and exposure to organic contaminants

    Page(s): 104 - 109
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    Activated‐break arc durations have been measured for various organic compounds and contact metals. These durations were determined as a function of exposure (partial pressure of organic contaminant times the contact open time) for each metal and organic compound. The metals studied were palladium, gold, silver, rhenium, 60 Pd‐40 Ag, and 73 Pd‐27 Ni (wt%). Organics used were diethylphthalate, isopropyl alcohol, trichlorotrifluoroethane (Freon 113), benzene, n‐hexane, cyclohexane, and phenol. The experimental results show three separate regimes with respect to exposure and agree well with the previous models of contact activation which have been generalized to include constant arc durations at short exposures. The steady‐state average arc duration, which is proportional to contact erosion, was found to be a function of both the contact material and exposure for a particular organic material. The data has been statistically analyzed and the results indicate that in the adsorption‐site‐limited regime (high exposure) the metals can be divided into groups according to their activation susceptibility, while the organic materials all belong to a single group. In the diffusion‐limited regime (intermediate exposure) ranking was observed for both the metals and organics, with larger differences noted for the organics. Finally in the initial activation region (low exposure) the individual differences between the organic or metal effects cannot be distinguished to 95% confidence. However, the degree of activation of a specific metal‐activant pair can be quite different than that expected from the average behavior of the metal over all activants, and the average behavior of the activant over all metals. Thus the metal‐activant pair is critically important in establishing the degree of activation. View full abstract»

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  • Plasma confinement by high‐power excitation in a waveguide

    Page(s): 110 - 113
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    Under TE20 mode excitation, the electric field in a rectangular waveguide is minimum at the center and has two intensity maxima at intermediate points. Consequently, the plasma electrons experience a strong ponderomotive force and are redistributed to assemble around intensity minima. A self‐consistent solution of the wave equation for this problem reveals that the plasma density around intensity minima may be enhanced by a factor of 10 for accessible rf power. It also suggests that the electromagnetic waves of frequency less than the plasma frequency ωp can penetrate a dense plasma. In a collisional plasma, the redistribution of electrons is predominantly caused by their inhomogeneous heating by the wave. The confinement in this case may be attained at much lower powers. View full abstract»

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  • Rise time and time‐dependent spark‐gap resistance in nitrogen and helium

    Page(s): 114 - 117
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    The rise time and time‐dependent spark‐gap resistance in nitrogen and helium were measured using a novel microwave method. Empirical formulas for spark‐gap resistance and rise time are proposed, with a maximum error, as compared to experimental results, of ±8%. View full abstract»

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  • Measurements of large ion currents in a pinched relativistic electron beam diode

    Page(s): 118 - 124
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    We have observed ion currents of 10–20% of the total diode current in a diode exhibiting pinched electron flow. Measurements have been made utilizing two independent techniques—multiple Faraday cups, and neutron generation and counting. The results agree well with each other and are compared with both numerical simulations and an analytic model of ion flow. Agreement is found to within the accuracy of the experimental measurement, lending further credence to the theoretical models. View full abstract»

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  • Multichannel laser light scattering diagnostics for density profile measurements in belt pinch plasmas

    Page(s): 125 - 128
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    A multichannel laser light scattering system with high sensitivity has been applied to Thomson scattering measurements of electron density profiles by a single laser shot. The problems inherent to radial profile measurements of toroidal plasmas were overcome and the stray light level could be lowered to ne =1013 cm-3 equivalent. This diagnostics was used for optimizing the preheating discharge in the Garching High‐Voltage Belt Pinch at low densities ne?1013 cm-3. View full abstract»

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  • Electromagnetic properties of thin epitaxial Bi films in magnetic fields up to 85 kG

    Page(s): 129 - 132
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    Electromagnetic measurements on thin epitaxial Bi films (thickness: 350–6350 Å) were carried out in magnetic fields up to 85 kG. The transverse magnetoresistance had a tendency of saturation with increasing magnetic fields. The tendency was stronger for thinner films. This behavior was attributed to the scattering at the grain‐boundary planes parallel to the electric field. In the measurements of longitudinal magnetoresistance, the momentum value of carriers estimated from the positions of peaks or shoulders in the magnetoresistance–vs–magnetic‐field curve was about 0.8×10-21 g cm/sec and agrees with the bulk Bi value. The appearance of peaks or shoulders can be interpreted by the partial diffuse scattering of carriers at film surfaces. Shubnikov–de Haas oscillations were observed in (dρ/dH) ‐H measurements. The oscillation period Δ (H-1) was found to depend on film thickness and the dependence was attributed to the thickness dependence of carrier densities in films. The oscillations caused by quantum size effect were not observed. View full abstract»

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Aims & Scope

Journal of Applied Physics is the American Institute of Physics' (AIP) archival journal for significant new results in applied physics

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Editor
P. James Viccaro
Argonne National Laboratory