摘要:

Bitter pattern observations are reported on domain walls in ion‐implanted garnet layers. Particular attention is given to the behavior of charged walls at the edge of nonimplanted disks and other elements and on the response of these walls to varying in‐plane fields. The interaction between bubbles and charged walls has been observed and the propagation of bubbles around disks and along propagation tracks has been examined. The crystalline symmetry of the garnet layer has been found to give rise to significant orientation effects on the response of walls to external fields. From a study of wall behavior certain characteristics of bubble motion along propagation paths can be explained.

ISSN:0021-8979    

DOI:10.1063/1.326689

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Properties of magnetic anisotropy of an ion‐implanted layer on [111]‐oriented bubble garnet films have been studied in relation to implantation dosages by ferromagnetic resonance techniques. As has been reported, subpeaks generated in the implanted layer were observed in addition to the main peak related to the garnet film itself. The resonant field of these subpeaks showed a strong dependence on the orientation in the (11¯0) plane, whereas dependence was weak in the (111) plane. Data was analyzed under the assumption that signals from the implanted region of specimens are of uniform mode, and it was found that implanted layers of a Y1.33Eu0.2Yb0.57Ca0.9Ge0.9Fe4.1O1@qL2film implanted with neon at an energy of 100 keV with dosages ranging from 1.1×1014to 2.0×1014/cm3were magnetically uniaxial, the easy axis being the (111) plane and the hard axis, the [111] axis. A precisely defined method for determining implantation‐induced anisotropy was developed, and results showed that its magnitude is several 104erg/cm3. Proton‐implanted specimens were also investigated.

ISSN:0021-8979    

DOI:10.1063/1.326690

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The effects of eddy currents on the nuclear magnetic resonance of Al27wires was determined for specimens with three significantly different diameters. The absorption and dispersion line‐shape derivatives, obtained at room temperature using a saturation factor (&ggr;2H21T1T2) much less than unity, were in agreement with theory.

ISSN:0021-8979    

DOI:10.1063/1.326691

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The effect of the loading factor (the ratio of the conductive volume to the total volume) of a composite can lead to errors of 20% if not considered when interpreting dielectric‐loss measurements. Free‐carrier interfacial polarization is shown to be unimportant in the interpretation of the Maxwell‐Wagner effect for certain classes of composites contrary to currently accepted thought, whereas it can be important in the interpretation of the Dember effect for the same materials. Non‐Debye loss in cases where free‐carrier interfacial polarization is unimportant is shown to be caused by an additional frequency‐dependent component of the conductivity, e.g., that caused by dipole reorientation or conformational rearrangement.

ISSN:0021-8979    

DOI:10.1063/1.326692

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We have used selective laser excitation techniques to investigate the spectroscopic properties of Nd3+ions in Y3(Al1−xGax)5O12crystals and found the mixed crystal nature of the host produced both distinct structure and inhomogeneous broadening in the Nd3+spectra. We employed time‐resolved spectroscopy measurements to characterize energy transfer between Nd ions in nonequivalent crystal field sites and the results are consistent with the migration of energy among Nd ions in the dominant type of site with trapping occurring at Nd ions in defect sites. The migration and trapping processes require thermal activation and are consistent with a two‐phonon assisted energy transfer mechanism. The efficiency of energy transfer is greater in mixed crystals than in unmixed garnet hosts, and it is shown that this is associated with the increase in the transition matrix elements in the mixed crystals.

ISSN:0021-8979    

DOI:10.1063/1.326693

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The full average radiation intensity of electrons and positrons channeled between crystal planes is calculated. Comparison of the results of these calculations with calculations using the parabolic approximation for the potential well of a channel is presented. The difference can in extreme cases reach two orders of magnitude. Estimates for the positions of the maxima of the frequency spectra are given. The number of quanta averaged over the angular distribution of the particles in a beam are found.

ISSN:0021-8979    

DOI:10.1063/1.326694

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The electrochromic performance of all solid‐state cells employing phosphotungstic acid and phosphomolybdic acid is reported. These cells employ SnO2as the viewing electrode and graphite as the back electrode. Diffuse reflectivity changes of ∼50% are readily achieved in ∼10 msec. The cells, in the bleached state, can be made white to red, and become black in the colored state.

ISSN:0021-8979    

DOI:10.1063/1.326695

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Compton profiles of glassy carbon and polycrystalline graphite were measured with AgK&agr;‐fluorescence radiation and a LiF 400 analyzer at a scattering angle of 160°. After some corrections, the projections of the momentum densities for the valence electrons as well as the radial‐momentum densities are obtained. The valence electron configurations show differences by comparing the individual profiles. A comparison with free‐atom Hartree‐Fock calculations demonstrates that the electronic state of glassy carbon is closer to the free atomic model than graphite.

ISSN:0021-8979    

DOI:10.1063/1.326696

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Terbium (+3) ions doped into zinc sulphide in the presence of neodymium trifluoride were excited by an electroluminescent process. The ZnS host lattice was in the form of a thin film made by vacuum deposition. Metallic electrodes attached to the ZnS film allowed a voltage to be applied to the device. Electroluminescence was observed through one of the electrodes after a short voltage pulse was applied. Measurements were made on the decay time of the5D4‐7F5line of the Tb+3ions. Changes in the decay time of this line were observed when the concentration of NdF3was varied. Photon‐counting techniques were used to measure the decay of the excited Tb+3ions. A decay‐rate theory based on resonance energy transfer between impurity ions in substitutional sites of the ZnS lattice was found to be in good agreement with the experimental data.

ISSN:0021-8979    

DOI:10.1063/1.326697

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The secondary emission coefficient &dgr; of evaporated Na3AlF6films is found to decrease from about 5.0 to 1.8 and then to increase again to between 5.0 and 6.0 under the influence of electron bombardment with 300‐eV electrons. These changes are associated with a decrease of over 2 eV in the surface work function. The initial decrease in &dgr; is caused by loss of fluorine, producing a surface consisting of metallic sodium and aluminum. During this period the Na and AlKLLAuger peaks shift to higher energy. The subsequent increase in &dgr; is associated with oxidation of the metallic sodium, the final surface composition being close to Na2O. This oxidation can be caused by CO2, O2, or H2O. Electron bombardment of the final oxidized surface produces a small reversible increase in &dgr; and a decrease in the work function. Initial experiments on films of other metal halides indicate that electron bombardment causes similar changes in &dgr; and surface composition.

ISSN:0021-8979    

DOI:10.1063/1.326698

出版商:AIP    

年代:1979

数据来源: AIP