摘要:

The spontaneous reorientation of the weak ferromagnetic moment (``temperature‐induced spin flop'') in the rare earth orthoferrites is found to take place over a well‐defined temperature range. In TmFeO3, this range is 12°K wide and centered at 88°K. Susceptibility peaks have been observed at the ends of this temperature interval where the magnetic easy axis just begins to rotate away from theaorcaxis.

ISSN:0003-6951    

DOI:10.1063/1.1755118

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A drift wave instability in a fairly highly ionized (50–90%) plasma column has been observed and its properties have been readily discovered using real time auto‐ and cross‐correlation techniques.

ISSN:0003-6951    

DOI:10.1063/1.1755119

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Enhancement of quantum efficiency has been observed in photocathodes as a result of the application of external electric fields. The magnitude of the enhancement was found to be a function of photon energy.

ISSN:0003-6951    

DOI:10.1063/1.1755120

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A pulsed laser source has been developed, which is continuously tunable from 4820 Å to 5790 Å, with power in the kilowatt range, and spectral width ≈14 cm−1. The technique used frequency addition in KDP. One frequency was that of a Nd‐glass laser, while the other frequency was selected by phase matching, from the continuum produced by self‐focusing and small‐scale trapping of the laser beam in CS2. Methods are outlined of extending the wavelength range to ≈50% of the 0.25 &mgr; to 1.0 &mgr; spectrum available with KDP and KD*P.

ISSN:0003-6951    

DOI:10.1063/1.1755121

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Measurements have been made onn‐type Ge at 77°K and 27°K, which show the existence of a bulk negative differential conductivity at electric fields above about 3 kV cm−1. This effect is believed to be the cause of previously observed current oscillations, and of traveling domains of high electric field which we have now observed at 27°K.

ISSN:0003-6951    

DOI:10.1063/1.1755122

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A method is described for enhancing the sensitivity of the thin films of certain oxides to small amounts of airborne hydrogen and other reducing gases. The quantitative behavior of thin films of platinum‐activated tungsten oxide is illustrated.

ISSN:0003-6951    

DOI:10.1063/1.1755123

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The thickness of films (<900 Å) of silicon dioxide on silicon can be determined by observation near Brewster's angle for silicon with the light polarized in the plane of incidence. Since the intensity of the reflected light increases with thickness for these films, the measurement is made by direct comparison of the light reflected by a sample with a calibrated SiO2on silicon ``thickness gauge.'' Film thicknesses can be estimated to an accuracy of about±30 Å for thicknesses less than 150 Å and±50 Å for thicknesses between 150 Å and 900 Å.

ISSN:0003-6951    

DOI:10.1063/1.1755124

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Voids were produced by the precipitation of excess quenched‐in vacancies in aluminum. The annealing of these voids in thin foil specimens by a self‐diffusion mechanism was studied using transmission electron microscopy. The annealing rates of both isolated voids and voids which were connected to the foil surfaces by dislocations were observed. The voids which were hooked up to the surfaces by dislocations annealed out at appreciably higher rates than the isolated voids. The results indicate that the dislocations acted as rapid self‐diffusion pipes for the transport of atoms into the voids from the surfaces.

ISSN:0003-6951    

DOI:10.1063/1.1755125

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A special laser cavity made by two roof‐top prisms each with roof angle smaller than 90° is described here. Such a cavity has the unique property of giving pure transverse modes of very high quality in pulsed operation.

ISSN:0003-6951    

DOI:10.1063/1.1755126

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Electrotransport in thin Al strips was directly observed by transmission electron microscopy. As expected, hole formation was seen in regions where the electron flow was in the direction of increasing temperature. Hillocks and whiskers were seen to form where the electron flow was in the direction of decreasing temperature. Cine´ films taken of the process show the holes to grow predominantly by a transverse movement of narrow fingers which ultimately coalesce and lead to a catastrophic strip burn‐out.

ISSN:0003-6951    

DOI:10.1063/1.1755127

出版商:AIP    

年代:1967

数据来源: AIP