摘要:

A mechanism is proposed to explain depolarization phenomena that have been observed in thin ferroelectric films and related multilayer devices. It is shown that, for a short‐circuited electrode‐ferroelectric structure, incomplete compensation of the ferroelectric polarization charge results when the center of gravity of this charge and the free compensation charge are not coincident. Depolarization fields in the ferroelectric arising from such incomplete compensations are estimated. A simple switching calculation shows such fields to be of sufficient strength to account for the initial polarization decay rate observed in Pb0.92Bi0.07La0.01(Fe0.405Nb0.325Zr0.27)O3films. The results of measurements involving changes in film thickness, electron concentration in the electrodes, and contact materials will be discussed and shown to be consistent with the mechanism proposed.

ISSN:0021-8979    

DOI:10.1063/1.1662770

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The structure and thermal stability of bimetallic Au‐Ta films has been studied by x‐ray diffraction, electrical resistivity, and by microscopy. Annealing above 450 °C forms a TaAu compound. The growth of the TaAu layer at the Au&sngbnd;Ta interface follows a parabolic rate law. A low‐temperature depletion of gold at tantalum grain boundaries occurs below 350 °C with an activation energy of 0.41 eV. Grain growth occurs with an activation energy of 0.50–0.55 eV for gold and 0.40–0.50 eV for tantalum. Thermal stresses of the order of 1.0×109dyn/cm2exist in the sputtered films.

ISSN:0021-8979    

DOI:10.1063/1.1662771

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The elastic properties of tantalum have been investigated over the temperature range 4.2–300 K. The values of the adiabatic elastic constantsC11,C44, andCL=(1/2) (C11+C12+2C44) at 4.2 K in units of 1012dyn/cm2are, respectively, 2.70, 0.873, and 3.02. The Debye temperature was calculated from the elastic constants and found to have the value of 265 K at low temperature. The elastic constants become temperature independent at low temperatures and approach linear behavior at high temperatures. In contrast to the normal behavior of the elastic constants, nuclear acoustic resonance experiments show anomalous line broadening.

ISSN:0021-8979    

DOI:10.1063/1.1662772

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Sensitivity enhancement factors predicted by an analysis of cw ultrasonic resonator systems using the propagating wave model are verified. Absorption and dispersion sensitivity factors were obtained by producing small changes in the acoustic properties of a CdS resonator with a light beam.

ISSN:0021-8979    

DOI:10.1063/1.1662773

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The thermal conductivity of CdSxSe1−x(0≤x≤1) solid solutions was measured between 100 and 300 °K. Analysis of the experimental data shows that normal processes played an important role in phonon scattering, and that mass and strain fluctuations equally contribute to thermal resistivity in the temperature range studied.

ISSN:0021-8979    

DOI:10.1063/1.1662774

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A study by internal friction and Young's modulus measurements has been made on high‐purity polycrystalline aluminum of the effects on dislocation damping by 1‐MeV electron irradiation in the temperature range 78–360 °K. These measurements confirm the presence of an internal friction ``peaking'' effect in aluminum in agreement with the defect dragging model proposed by Simpson and Sosin. In particular it is observed that during electron irradiation and for specific mechanical and thermal histories of the sample, the logarithmic decrement &dgr; increases and later decreases. The increase is found to be generally strain amplitude independent and to be highly structure dependent, disappearing after a suitable high‐temperature anneal. Simultaneous modulus measurements show little or no effect due to electron irradiation between 78 and 240 °K, but the modulus increases monotonically for irradiations above 240 °K. The corresponding point‐defect kinetics exhibit a complex annealing behavior.

ISSN:0021-8979    

DOI:10.1063/1.1662775

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The transport of a sheet of excess carriers in a conducting material having two types of mobile carriers is described in a small‐signal approximation. It is shown that the carriers exhibit an equivalent diffusion in the drift direction due to the dielectric relaxation effect even in the absence of thermal diffusion, and that the total effective diffusion coefficient is given by the sum of the thermal diffusion coefficient and the two‐carrier diffusion coefficient.

ISSN:0021-8979    

DOI:10.1063/1.1662776

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The x‐rayKabsorption spectra of the constituent atoms in fcc solid solutions of Mn in Cu, Ni, Co, and Fe show systematic changes taking place with increasing manganese concentration which it is not possible to explain in terms of the rigid‐band model for alloys. A decline in the initial rise in absorption with increasing Mn content is observed for all absorption edges except for Mn in Mn&sngbnd;Fe solid solutions, in which case an increase takes place. A tentative explanation, based on hybridization of the outer states upon alloying, is proposed for Mn&sngbnd;Cu and Mn&sngbnd;Ni alloys.

ISSN:0021-8979    

DOI:10.1063/1.1662777

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The surface of sheets of polyethylene was studied by means of a scanning electron microscope in order to compare the effects of corona discharges and those of the constituents of the discharge, i.e., uv radiation and electrons and O+ions of low energy. The deterioration produced by the O+ions resembles that produced by the discharge, and the deterioration produced by the electrons and the uv radiation does not. This difference tends to confirm infrared results and the assumption that the ions concentrated at the tip of a discharge erode the surface of the insulating material.

ISSN:0021-8979    

DOI:10.1063/1.1662778

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

An analysis for scattering of scalar waves in air by a wake on the surface of water is developed. The wake on the water surface is generated as a concentrated pressure point travels over the free water surface. The wake has characteristics resembling a diffraction grating. The grating produces maximum constructive interference (resonance) in the backscattered wave under certain conditions. At resonance the scalar wavelength, water wavelength, and angle of incidence satisfy a simple geometrical condition.

ISSN:0021-8979    

DOI:10.1063/1.1662779

出版商:AIP    

年代:1973

数据来源: AIP