摘要:

The magnetic properties of rf sputtered Ni81Fe19films were studied as a function of thickness from<100 to ∼1200 Å. In contrast to some recently reported studies, there was no evidence of an oscillatory dependence of resistivity on Δρ as a function of thickness. The magnetoresistance, resistance, coercivity, and anisotropy field varied smoothly with thickness. In contrast, the magnetostriction λshad a minimum of −1.5×10−6at ∼300 Å. The saturation magnetic moment did not decrease with thickness over the thickness range studied here. The derived magnetoresistance of an ‘‘infinitely’’ thick film was 3.92% compared to the bulk value of ∼4%. The analysis indicates that surface and grain‐boundary scattering are the primary cause of lower than bulk values of magnetoresistance in these thin permalloy films.

ISSN:0734-2101    

DOI:10.1116/1.577232

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

A modified two‐layer thermal barrier coating (TBC) was studied. In this work, the vacuum plasma sprayed Co–29Cr–6Al–1Y bond coat (first layer) received a pack aluminizing treatment prior to deposition of the air plasma sprayed ZrO2–8‐wt. %Y2O3top coat (second layer). The effects of this treatment on the properties of plasma sprayed thermal barrier coatings were evaluated by thermal cycing tests in air within the temperature range from 1000 to 1150 °C. Results of experiments showed that the performance of TBC can be improved by the prior aluminizing treatment on Co–29Cr–6Al–1Y bond coat. This treatment was found to be very effective in reducing the oxidation rates of the bond coat. The fractographic analyses were also conducted on the spalled specimens to elucidate the performance improving mechanisms of TBC effected by the attempted prealuminizing treatment on the bond coat.

ISSN:0734-2101    

DOI:10.1116/1.577233

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The effect of thermal processing on thin films ≲1000 Å of permalloy and a permalloy alloyed with Rh has been examined. Coercivity, anisotropy field, and magnetostriction were measured both before and after annealing for 30 min. The films were exposed to temperatures representative of those employed in thin‐film head fabrication, 92 and 185 °C anneals representing photo processes and 240 °C approximating the highest temperatures used during thin‐film head processing. Significant changes occurred in the thinner films after the 185 and 240 °C anneals. Changes were observed in both types of films. The largest occurred in the permalloy films. The magnetostriction of both film compositions became significantly more negative after annealing at the higher temperatures, with the change in the Rh alloy films smaller. The changes in properties decreased with increasing thickness for both permalloy and the Rh alloy. Auger electron spectroscopy analysis has shown that the differences before and after annealing at the higher temperatures result from oxidation of the upper (exposed) surface of the films. These studies show that the magnetic properties, especially magnetostriction, are strong functions of the process history of permalloy thin films.

ISSN:0734-2101    

DOI:10.1116/1.577234

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Vapor‐deposited films prepared under low adatom mobility conditions commonly exhibit columnar structures. We present the scanning electron microscopy study of Cu films with a thickness around 3.7 μm deposited on rough Al2O3ceramic substrates and smooth SiO2substrates. The Cu films were deposited using the partially ionized beam deposition technique under the same deposition conditions. The films deposited on the rough substrates have a typical columnar structure while those deposited on the smooth substrates are noncolumnar. The complete difference in physical structures is due to the difference in the substrate surface roughness. The results indicate that in any structure zone model for the physical structure of the film the substrate surface roughness is an important parameter and cannot be neglected. It is reasoned that the adatom surface diffusion length, which is determined by the deposition conditions, serves as a critical measure for the length scale of surface roughness. At the initial stage of the film growth, the columnar structure develops only for the roughness with a length scale longer than adatom surface diffusion length.

ISSN:0734-2101    

DOI:10.1116/1.577235

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

(100) oriented Cr/Fe/Cr and Pd/Fe/Pd sandwich structures have been deposited on (100) Si using the epitaxially grown (100) Pd/Cu and (100) Cu, respectively, as the seed, in a vacuum of low 10−7Torr. Four structures each are compared, with a Fe thickness of 25, 50, 100, and 500 Å, keeping the Cr and Pd layers at 1000 Å. No reversal in anisotropy is observed between the in‐plane and normal‐to‐plane magnetization over the entire Fe thickness range studied. The in‐plane epitaxial relation determined among the metals allows a study of the magnetocrystalline anisotropy of Fe in these structures also. Both the Cr/Fe/Cr and Pd/Fe/Pd structures show an easier magnetization at low field along the [100] edge than the [110]one, with the Cr/Fe/Cr structures being more pronounced. Magnetizations along these two edges approach each other at higher field. These are the same as that of bulk Fe crystal. The possible lattice deformation of the Fe layers in these structures is also explored.

ISSN:0734-2101    

DOI:10.1116/1.577236

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

We have used ultrahigh vacuum dc magnetron sputtering to deposit cobalt–palladium multilayers on silicon substrates. The films have been characterized using vibrating‐sample magnetometry, x‐ray diffraction, and cross‐sectional transmission electron microscopy. We have observed ways in which the films’ microstructures and magnetic properties vary as the sputtering pressure is altered, and related the changes in magnetic properties to the changes in microstructure.

ISSN:0734-2101    

DOI:10.1116/1.577237

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Thin films of copper, germanium, and zinc were deposited at an argon pressure of 2.7 Pa (20 mTorr) on cover glass substrates precoated with 10 nm of Au/Pd. The substrate temperaturesTsranged from 77 to 417 K for zinc, 77 to 543 K for copper, and 77 to 490 K for germanium. The discharge voltage was varied from 900 to 1300 V. Average film thickness was ∼1.5 μm, with deposition rate ∼0.4 μm/min. Ion energies were measured by the retarding field method. Examination of the film structure with a scanning electron microscope (SEM) showed that zonesIandTwere missing. Structural zone transition temperatures were lower than in the models proposed by Movchan and Demchishin, and Thornton. All copper and zinc films were polycrystalline. Germanium, for the above deposition rates, showed an amorphous/poly‐ crystalline transition, as determined by reflection high‐energy electron diffraction, for various ion energy andTscombinations. Polycrystalline germanium is observed at room temperature for energies above 340 eV. A structural zone model showing the effect of the ion energy and substrate temperature on the film structure for ion plated films is proposed.

ISSN:0734-2101    

DOI:10.1116/1.577238

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The resonance frequency shifts of a glass thin plate vibrated by a photothermal effect have been measured in the pressure region from 10−4to 760 Torr for He, Ne, Ar, Kr, and Xe gas. The frequency shift in the pressure region above 100 Torr is caused by the viscous drag of the gas and that below 1 Torr is due to the thermal conduction of the gas.

ISSN:0734-2101    

DOI:10.1116/1.577239

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Examined has been the performance of cryogenic fuel loading into a spherical foam shell target for laser fusion program by means of thermal cavitation technique to nondestructively measure the loaded fuel massinsitu. Experimental results on the loaded mass by means of the thermal cavitation technique ranged from 95% to 135% of the fully saturated fuel mass, which was measured by the resonance elastic vibration technique. In order to discuss the variation in loaded fuel mass, we have analyzed the exact bridge profile formed between the shell and the liquid fuel surface and the capillary binding force. Sublimation of the loaded fuel before the laser irradiation is considered to achieve quantitatively controlled accurate fuel loading, including fuel shrinkage by phase changing and the incoming thermal radiation circumstantially.

ISSN:0734-2101    

DOI:10.1116/1.577240

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

High quality, microdeuterated polystyrene shells were fabricated using a density‐matched emulsion method. The diameter and wall thickness of the shell ranged from 100 to 1500 and 3 to 15 μm, respectively. The sphericity, the wall thickness uniformity, and the surface smoothness were 99.8%, 99.3% and<0.1 μm, respectively. A defect on the inner surface of the shell was smeared by replacing water in the shell with ethanol prior to the final drying process.

ISSN:0734-2101    

DOI:10.1116/1.577241

出版商:American Vacuum Society    

年代:1991

数据来源: AIP