摘要:

Unexpectedly rapid oxygen diffusion has been observed at 25–250 °C in YIG films with uncompensated Ca additions of 0.1 to 0.23 atoms per formula unit. A 3‐&mgr;m‐thick film originally dark and conducting due to Fe4+lightened and became insulating in 15 min at 100 °C in a reducing saturated solution of FeCl2. A diffusion distance of ∼0.5 mm has been observed along a film in 25 h at 250 °C. A model is proposed based on the dependence of the diffusion coefficientDon oxygen vacancy concentration. A magnetic bubble garnet film containing Ca, which also lightened at 250 °C, showed no observable changes in the pertinent bubble parameters.

ISSN:0003-6951    

DOI:10.1063/1.89667

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Propagation of 80‐MHz surface acoustic waves on a single‐crystal substrate of Ho0.58Tb0.20Dy0.22Fe2in the presence of a magnetic field is reported. Phase velocity changes of 2%, accompanied by attenuation changes in excess of 30 dB, have been observed by varying the applied magnetic field. Measurements of velocity and attenuation variation with field magnitude and direction are presented along with qualitative explanations of the observed experimental behavior.

ISSN:0003-6951    

DOI:10.1063/1.89668

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

An acoustic domain in CdS crystals scatters a radiated optical beam near the intrinsic absorption edge. This paper presents work showing that the equivalent band‐gap alteration caused by the scattering effect is observed in 600–1000‐&mgr;m‐thick samples. This alteration is caused by the following: (i) In the CdS crystal the optical transmission of incident light withe∥cis larger than that for incident light withe⊥c(e: polarization of the incident light;c:caxis of the crystal). (ii) When the incident light is scattered by the shear acoustic wave in the sample, the plane of polarization is rotated by 90°. Therefore, the incident light withe⊥cbehaves as if it weree∥cand the optical transmission increases.

ISSN:0003-6951    

DOI:10.1063/1.89669

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Vitreous LiNbO3and LiTaO3have been prepared by roller quenching these compositions from the melt. The transparent glasses exhibit pronounced dielectric anomalies with peaks of &egr;≳105close to the crystallization temperature which are not characteristic of the crystalline phase. Pyroelectricity is induced after cooling the glass in an electric field. The data are discussed in terms of a simple theoretical model for amorphous ferroelectricity and interfacial polarization due to localized ionic motion.

ISSN:0003-6951    

DOI:10.1063/1.89670

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

The Bethe Age diffusion solution for high‐energy electrons in the presence of a magnetic field is derived. The electron transport in the presence of a magnetic field can generally be separated into diffusion along and perpendicular to the field direction. This result is similar to diffusion of a plasma in a magnetic field. However, unlike plasma diffusion, the energy of the fast electrons is retained as the independent variable.

ISSN:0003-6951    

DOI:10.1063/1.89671

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

The positron lifetime &tgr;1of Pd77.5Cu6Si16.5, Fe75P16B6Al3, and Ni75P16B6Al3glass increases from ∼170 ps to a plateau value ∼175 ps immediately following an anneal at 350 K for 30 min. With further annealing above 500 K, &tgr;1decreases and approaches ∼165 ps. Possible atomic clustering in metallic glasses during structural relaxation will be described.

ISSN:0003-6951    

DOI:10.1063/1.89672

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Compensation arising from ion damage has been investigated in InP. It is found that ≳10 times the irradiation that produces resistive layers in GaAs is required to similarly compensate InP. The damage anneals in two stages indicating that two distinct defects contribute to the carrier removal process. Partial annealing at ∼400 °C rather than at 500 °C as in GaAs is suggested as a means of producing low‐absorption highly resistive layers. From compensation considerations annealing to at least 550 °C will be required for dopant implantations if effective electrical utilization is to be achieved.

ISSN:0003-6951    

DOI:10.1063/1.89673

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Under the assumption that extracted beam energy is quickly shared among secondary cascade members of all masses, we present a model which accounts quantitatively for recently observed equilibrium surface enrichments in heavy atoms following ion bombardment of alloys and compounds. Assuming strong radiation‐driven diffusion, effects of which are directly observed, and given the time required to reach equilibrium, we can calculate the thickness &Dgr;xof the enriched layer. Alternatively, knowing &Dgr;x, a calculation of the equilibration time constant is possible.

ISSN:0003-6951    

DOI:10.1063/1.89652

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

We have investigated the role of the preionization cathode material and the preionization energy in high‐field preionized discharges of a CO2laser mixture at atmospheric pressure. Independent control of both theE/pand the input energy is demonstrated over a large range of values. These results are applicable to the design of waveguide lasers and other types of gas‐discharge devices.

ISSN:0003-6951    

DOI:10.1063/1.89653

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

A waveguide geodesic lens formed in a single‐mode Ti‐diffused LiNbO3waveguide is reported. The paraxial focal length of the geodesic lens fabricated was 1.1 cm. In addition, a novel technique for ultrasonic impact grinding of profiles of arbitrary shape was developed. The paper describes the first single‐mode geodesic lens fabricated in a LiNbO3substrate.

ISSN:0003-6951    

DOI:10.1063/1.89654

出版商:AIP    

年代:1977

数据来源: AIP