摘要:

Results on quenched condensed films of Bi, Sb,Sb+noblemetals, Ge,Ge+noblemetals, andSn+Cuare discussed in order to demonstrate the importance of the short-range order for the properties of such films. Two kinds of amorphous films can be clearly distinguished: (a) crystallinelike and (b) liquidlike amorphous films. This classification is important for materials which are partially covalently bonded. The results also show that an interesting relation exists between metastable phases in quenched condensed films and high pressure modifications of the same material.

ISSN:0022-5355    

DOI:10.1116/1.1318397

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

Both dc and rf currents are passed through a thin narrow film of tin such that the total current exceeds the critical currentic. Lowering the rf frequency from 1 GHz causes, at a reproducible frequencyωc, a step in the rf voltage away from the superconducting state toward the normal state. Increasing the dc increasesωcin accord with the empirical relation:idc+irf exp(−ωcτ)=ic. The time constant τ, which is a measure of the normal state nucleation time, is about10−9 secand is a function of temperature and ofirf. Second harmonics and phase shifts were observed.

ISSN:0022-5355    

DOI:10.1116/1.1318398

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

The possibility of forming the gold–lead intermetallic compoundsAu2Pb,AuPb2andAuPb3in tunnel structures using thin films of aluminum, aluminum oxide, lead, and finally gold is being studied. The room temperature diffusion of gold into lead films with thickness in the range 1000–3600 Å is found to be rapid, with indications of compound formation taking place within a few hours. Variation of the thickness ratio of the lead and gold films is used to preferentially form a given intermetallic. Each intermetallic is characterized by its transition temperatureTc, energy gapΔo, and by a unique phonon spectrum which is reflected in the derivatives of the tunneling characteristics.

ISSN:0022-5355    

DOI:10.1116/1.1318399

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

Noble gas ion beam sputtering techniques have been used to prepare thin films of several transition metals. Thin films of Mo, Ti, W, and Zr metals have been found to be superconducting with transition temperatures substantially higher than those observed for the respective bulk metals. Cr thin films have been found to be superconducting for the first time. Ion beam sputtered thin films of Nb, Ru, Ta, and V metals were similarly deposited, resulting in decreases inTccompared with bulk values. In each case the transition temperatures were seen to depend on the noble gas used for deposition. The highest transition temperatures were obtained for those films deposited with xenon gas. Superconducting transition temperatures are correlated with the kind of gas used for deposition, the apparent particle size, and with changes in the size of the metal lattice.

ISSN:0022-5355    

DOI:10.1116/1.1318400

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

Thin luminescent films of lanthanum and gadolinium oxysulfide(RE2O2S)were prepared by radio-frequency sputtering in anAr–H2Smixture. Small additions of Eu, Tb, or Tm produced red, green, or blue emissions, respectively. A luminance of 40 000 ftL from aLa2O2S:Tbfilm was observed. The composition of the sputtered films was found to be very dependent upon theH2Spressure in the sputtering chamber. The film composition as a function ofH2Spressure was determined and described. In order to achieve maximum luminescence, the films were treated in anH2–SO2atmosphere at 1000 °C, and x-ray diffraction and luminous emission linewidths were observed to have decreased after treatment. Crystalline growth within the film and improved oxygen sulfur stoichiometry resulting from the treatment process are believed to be primarily responsible for the increase in luminous efficiency. The maximum luminous efficiency of the films was measured to be approximately 1/10 that of corresponding powder screens. Attempts to increase the film luminance by reducing the internal trapping of the radiation are discussed.

ISSN:0022-5355    

DOI:10.1116/1.1318401

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

Thin films of MgO were prepared by deposition from the vapor phase on amorphous and pylycrystalline substrates. Transmission and reflection electron diffraction were used to determine the orientation of the crystals in these MgO films. It was found that, on amorphous substrates initially at room temperature, the films possessed a crystal orientation which varied with film thickness. Films thinner than ∼ 500 Å showed a random orientation. As the film thickness was increased above ∼ 500 Å, a [111] preferred orientation was developed with an axis inclined away from the substrate normal and toward the direction of the vapor beam at oblique vapor incidence. At high substrate temperature(∼ 150–300 °C),the films followed the same behavior during growth. This preferred orientation is interpreted as a final growth orientation. On silver films as substrates, initially at room temperature, the same [111] preferred orientation was observed in films ≲ 100 Å thick and with increasing film thickness the orientation persisted. In thick deposits a slight inclination of the orientation axis was also observed at oblique vapor incidence. These results suggest that on Ag substrates the orientation is an initial nucleation orientation and also a final growth orientation.

ISSN:0022-5355    

DOI:10.1116/1.1318402

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

A series of tunneling measurements using Pb–Zn or ZnS–oxide–metal thin film junctions in the normal state is reported. The samples are prepared by depositing a film of Zn or ZnS on top of the first Pb film prior to oxidation. For both dopants a metallic Zn layer of monolayer thickness is present between the Pb and the insulator. A fraction of a monolayer of Zn is sufficient to substantially enhance the structure usually attributed to electrode phonons and to eliminate that usually attributed toPbOxbarrier phonons. The latter is replaced by structure which may be related to ZnO in Zn-doped junctions and ZnS in one type of ZnS-doped junctions. No barrier phonon structure whatever appears in a second type of ZnS-doped junction. The smooth background conductance is also modified by the doping. These results are discussed in terms of recent theoretical work. They suggest that the coupling to barrier and electrode phonons is at least as important in determining the tunneling characteristic as the phonon spectra themselves, and that the metal-insulator interface is critical in determining the coupling.

ISSN:0022-5355    

DOI:10.1116/1.1318403

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

The magneto-optical properties of magnetic materials in thin film form have been of considerable interest since thermal magnetic recording was demonstrated on MnBi. With the advances being made in materials research and laser technology, a laser addressed system may be realized. Material requirements necessary for thermal magnetic recording are discussed. A review is made of those materials whose magnetic and optical properties have been studied. By comparing the known material properties with the required properties for a laser addressed memory, this review shows that, at present, four recently discovered compounds have satisfactory properties for an optical storage system. These four are high temperature phase MnBi doped with Ti or Ni for stabilization, MnAlGe, MnGaGe, and amorphousGdCo5.

ISSN:0022-5355    

DOI:10.1116/1.1318404

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

In trying to determine the nature of the magnetization distribution in thin films having a periodic magnetic structure it is more convenient to work with the “magnetic” small angle diffraction pattern obtained in the electron microscope rather than the Lorentz image. The reasons for this will be discussed and two approaches to the analysis of the diffraction patterns will be described. The first method makes use of models of the magnetization distribution from which theoretical diffraction patterns may be computed for comparison with the observed data. The second method makes use of the Gerchberg-Saxton algorithm which may be applied directly to the intensity distribution in the diffraction pattern. The results of some preliminary studies using this algorithm will be discussed.

ISSN:0022-5355    

DOI:10.1116/1.1318405

出版商:American Vacuum Society    

年代:1973

数据来源: AIP

摘要:

Techniques have been developed with which it is possible to fabricate superconducting thin film structures (“bridges”) which show Josephson-like phenomena, with a wide variety of electrical and superconducting parameters. These bridges—based on the proximity effect—are made in layered thin film substrates which have been fabricated from many different, both hard and soft, superconducting materials. The fabrication techniques and the electrical and superconducting characteristics for these proximity effect bridges including a simple low frequency(≤ 10 GHz)equivalent circuit will be discussed. These bridges have been incorporated into simple thin film circuits for use as galvanometers, magnetometers, gradiometers, detector arrays, etc. Extension of these techniques to more complex superconducting thin film bridge circuits including resistors, capacitors, and inductors will be indicated.

ISSN:0022-5355    

DOI:10.1116/1.1318406

出版商:American Vacuum Society    

年代:1973

数据来源: AIP