摘要:

The pulse echo technique is employed to measure the acoustic wave attenuation along thecaxis of a single‐domain lithium niobate crystal at room temperature up tocband frequencies. Initial experiments show that the frequency dependence of the attenuation is nearly quadratic as predicted by theory. Approximately 13 dB of loss per &mgr;sec of time delay is observed at 5.5 GHz. The relatively low‐loss characteristics, coupled with the self‐transduction properties, make lithium niobate a leading candidate for microwave room‐temperature delay line applications.

ISSN:0003-6951    

DOI:10.1063/1.1754679

出版商:AIP    

年代:1966

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.1754680

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

Bicrystal metal films were prepared by electrodeposition of nickel on evaporated, single‐crystal copper films. Electron microscopic examination of the bicrystal films revealed interfacial dislocations which aid in reducing the misfit strain between the crystals. In both (100) and (111) bicrystals, misfit dislocations, aligned in <110> directions, were observed with Burgers vectors not contained in the interfacial plane. Glide of pre‐existing or surface nucleated dislocations is suggested as the method by which this type of misfit dislocation is produced.

ISSN:0003-6951    

DOI:10.1063/1.1754681

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

Switching effects have been observed in the current vs voltage curves ofn‐type GaAs diodes with resistivities between 0.3 and 5 &OHgr;‐cm. After switching, the diodes go into a constant‐voltage avalanche breakdown state with a sustaining field of 4500 V/cm. These effects are attributed to a peak in the hole generation rate &agr; between 3,000 and 10,000 V/cm caused by high energy electrons in the (000) valley of the conduction band.

ISSN:0003-6951    

DOI:10.1063/1.1754682

出版商:AIP    

年代:1966

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.1754683

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

p‐Type conductivity and stored electron charge densities as large as 1.3 × 10−7coul/cm2have been observed in high‐resistivity CdS crystals. These properties were studied by photovoltaic, photopolarization, and thermo‐electric power measurements.

ISSN:0003-6951    

DOI:10.1063/1.1754684

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

The magnetostriction constants &lgr;100and &lgr;111have been measured at room temperature for YIG single crystals in which a small fraction of the iron ions are replaced by silicon. The magnetically active impurity is believed to be divalent iron which compensates the Si4+. As the silicon concentration reaches about 0.05 Si atoms/Y3Fe5O12, both &lgr;'s pass through zero. In crystals of this composition the magnetization is largely decoupled from the strain distribution in the crystal. A peak in low‐frequency permeability and simple easily interpreted domain structures correspond to this &lgr; = 0 composition.

ISSN:0003-6951    

DOI:10.1063/1.1754685

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

Vacuum‐evaporated gold films were used as inert markers to study the oxidation mechanism of cobalt at 850°C. Gold‐marked and unmarked specimens were simultaneously oxidized for 138 hr. With the exception of the gold marker appearing as a dispersed row of spheriods within the CoO layer closest to the metal‐oxide interface, and the random distribution of voids in the specimens, the microstructures of the gold‐marked and unmarked specimens were identical, and are in agreement with microstructures reported in the literature.

ISSN:0003-6951    

DOI:10.1063/1.1754686

出版商:AIP    

年代:1966

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.1754687

出版商:AIP    

年代:1966

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.1754688

出版商:AIP    

年代:1966

数据来源: AIP