Magnetoresistance and Structure of Granular Co/Ag Thin Films

1993 ◽  
Vol 313 ◽  
Author(s):  
Mary Beth Stearns ◽  
Yuanda Cheng
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Room Temperature ◽  
Magnetization Measurements ◽  
X Ray ◽  
Conduction Electrons ◽  
Low Field ◽  
Co Concentration ◽  
Microscopy Techniques ◽  
Substrate Temperatures

ABSTRACTSeveral series of CoxAg1-x granular thin films (-3000Å) were fabricated by coevapora-tion of Co and Ag in a dual e-beam UHV deposition system at varying substrate temperatures. These films have low field magnetoresistance values as large as 31% at room temperature and 65% at liquid N2 temperature. The structure of the films was determined using magnetization measurements as well as x-ray and various electron microscopy techniques. The composition was determined using Rutherford backscattering spectroscopy. The Magnetoresistance was measured at both room and liquid N2 temperatures.We deduce from the magnetization and RBS Measurements that the films consist of Co globules embedded in a Ag Matrix and that there is no appreciable mixing of the Co and Ag atoms in the films deposited at substrate temperatures ≥ 400°K. The size of the Co globules is seen to increase with increasing Co concentration and the maximum magnetoresistance occurs in those films having the smallest Ag thickness which provides magnetic isolation of the Co globules.We suggest that the large magnetoresistance of these films arises from the same mechanism which causes the low field magnetoresistance in pure ferromagnets, namely, the scattering of the highly polarized d conduction electrons of the Co at magnetic boundaries. The large increase in the room temperature magnetoresistance of the CO/Ag films as compared to those of pure 3d ferromagnetic films is due to the distance between the magnetic boundaries being reduced to a few nanometers, because of the small size of the single domain Co globules, as compared to a few microns in 3d ferromagnets.

scholarly journals Properties of Nanostructure Bismuth Telluride Thin Films Using Thermal Evaporation

2017 ◽  
Vol 2017 ◽  
pp. 1-4 ◽  
Author(s):  
Swati Arora ◽  
Vivek Jaimini ◽  
Subodh Srivastava ◽  
Y. K. Vijay
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Bismuth Telluride ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Scanning Electron

Bismuth telluride has high thermoelectric performance at room temperature; in present work, various nanostructure thin films of bismuth telluride were fabricated on silicon substrates at room temperature using thermal evaporation method. Tellurium (Te) and bismuth (Bi) were deposited on silicon substrate in different ratio of thickness. These films were annealed at 50°C and 100°C. After heat treatment, the thin films attained the semiconductor nature. Samples were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to show granular growth.

Structure of CoxAg100-x and Its Relation to GMR

1992 ◽  
Vol 286 ◽  
Author(s):  
John Q. Xiao ◽  
J. Samuel ◽  
C. L. Chien
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Composition Range ◽  
Magnetic Scattering ◽  
Granular System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Concentration

ABSTRACTWe have studied the structure of the Co-Ag granular system across the entire composition range, as well as the annealed samples, using transmission electron microscopy (TEM) and x-ray diffraction. GMR, as much as 80% at 5K and 25% at room temperature, have been observed. The absolute values of the resistivity (ρ) and the change of the resistivity (δρ) as functions of the magnetic Co concentration and the annealing temperature have been determined. A linear relation between δρ and I/rco, where rco is Co particle size, has been found. This result suggests that the magnetic scattering at the interfaces is crucial to GMR.

Microstructure and Properties of CoSi2 Thin Films on (100) Silicon by Laser Physical Vapor Deposition

1992 ◽  
Vol 285 ◽  
Author(s):  
P. Tiwari ◽  
R. Chowdhury ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructure And Properties ◽  
Transmission Electron ◽  
Substrate Temperatures ◽  
Deposited Films

ABSTRACTLaser physical vapor deposition (LPVD) has been used to deposit thin CoSi2 films on (001)silicon at different substrate temperatures ranging from room temperature to 600°C. Particulate-free silicide thin films were characterized by X-ray diffraction, Rutherford backscattering, and high resolution transmission electron microscopy. We have found that films deposited at 200°C and below are amorphous; 400°C deposited films are polycrystalline whereas films deposited at 600°C are of epitaxial nature. The Effect of subsequent annealing on resistivity of room-temperature deposited thin films has been investigated. The resistivity value decreases to less than 15 μΩcm after annealing making these films suitable for microelectronics applications. The correlation between microstructure and properties of these films are discussed.

Heteroepitaxial Growth of Epitaxial C60-Thin Films on Mica(001)

1994 ◽  
Vol 359 ◽  
Author(s):  
S. Henke ◽  
K.H. Thürer ◽  
S. Geier ◽  
B. Rauschenbach ◽  
B. Stritzker
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Substrate Temperature ◽  
Room Temperature ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Substrate Temperatures

ABSTRACTOn mica(001) thin C60-films are deposited by thermal evaporation at substrate temperatures from room temperature up to 225°C. The dependence of the structure and the epitaxial alignment of the thin C60-films on mica(001) on the substrate temperature and the film thickness up to 1.3 μm at a well-defined deposition rate (0.008 nm/s) is investigated by atomic force microscopy and X-ray diffraction. The shape and the size of the C60-islands, which have an influence on the film quality at larger film thicknesses, are sensitively dependent on the substrate temperature. At a film thickness of 200 nm the increase of the substrate temperature up to 225°C leads to smooth, completely coalesced epitaxial C60-thin films characterized by a roughness smaller than 1.5 nm, a mosaic spread Δω of 0.1° and an azimuthal alignment ΔΦ of 0.45°.

MOCVD Growth of Epitaxial SrTiO3 Thin Films on YBa2 Cu3O7−x/LaAlO3

1993 ◽  
Vol 335 ◽  
Author(s):  
S. Liang ◽  
C. Chern ◽  
Z. Q. Shi ◽  
Y. Lu ◽  
P. Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Ac Susceptibility ◽  
Superconducting Property ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mocvd Growth ◽  
Transmission Electron ◽  
Substrate Temperatures

AbstractStrontium titanate (SrTiO3) thin films have been epitaxially grown on YB2Cu3O7−x (YBCO)/LaAlO3 at substrate temperatures of 660 to 700°C. X-ray diffraction (XRD) results indicated that single crystalline SrTiO3 thin films were epitaxially grown on the substrate with <100> orientation perpendicular to the substrates. The compositions of the films with different growth conditions were examined by Rutherford backscattering spectroscopy (RBS) and energy dispersive x-ray spectroscopy (EDX). The ratio of Sr/Ti is in the range of 0.9 to 1.1 for the films with a thickness of 1000–2000Å. The surface morphology of the films and the interfaces of the SrTiO3/YBCO structure were examined by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Very smooth surface and sharp interface were observed. The superconducting property of the YBCO layer, as measured by ac susceptibility, did not degrade after growth of SrTiO3 film. The dielectric constant as high as 320 was obtained at 100KHz. The leakage current density is less than 1×10−6A/cm2 at 3V operation.

X-ray, electron microscopy and photovoltaic studies on CdTe thin films deposited normally at different substrate temperatures

1990 ◽  
Vol 25 (12) ◽  
pp. 4987-4991 ◽  
Author(s):  
S. Saha ◽  
U. Pal ◽  
B. K. Samantaray ◽  
A. K. Chaudhuri ◽  
H. D. Banerjee
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
X Ray ◽  
Cdte Thin Films ◽  
Substrate Temperatures

Synthesis of Chemical Responsive Chitosan–Grafted-Polyaniline Bio-Composite

2011 ◽  
Vol 306-307 ◽  
pp. 82-86 ◽  
Author(s):  
S. K. Shukla ◽  
Ashutosh Tiwari
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Graft Copolymerization ◽  
Radical Copolymerization ◽  
Probable Mechanism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Experimental Findings ◽  
Microscopy Techniques ◽  
Scanning Electron

A polysaccharide based bioplolymer, chitosan was grafted with polyaniline through a simple room temperature oxidative-radical copolymerization method employing CuSO4 as a polymerizing agent. The grafting conditions were optimized by varying different parameters. The optimized experimental findings have been discussed and proposed a probable mechanism for the graft copolymerization. The representative sample of chitosan-graft-polyaniline (CHIT-g-PANI) was characterized using UV-vis, FTIR, X-ray diffraction and Scanning electron microscopy techniques taking chitosan as reference material. The result revealed the formation of grafted composite. Which exhibited highly improved electrical conductivity , in the order of ~ 10 -6 times due to the grafting of PANI onto chitosan backbone. Further , composite was found responsive in nature for H+ ion , which will be a suitable properties for its use in fabrication of bio-sensor.

scholarly journals Synthesis and Properties of Epitaxial Thin Films of c-axis Oriented Metastable Four-Layered Hexagonal BaRuO3

1999 ◽  
Vol 602 ◽  
Author(s):  
M. K. Lee ◽  
C. B. Eom ◽  
W. Tian ◽  
X. Q. Pan ◽  
M. C. Smoak ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Room Temperature ◽  
Layered Compounds ◽  
Epitaxial Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Novel Device ◽  
Transmission Electron ◽  
Device Applications

AbstractWe have grown epitaxial thin films of metastable four-layered hexagonal (4H) BaRuO3 on (111) SrTiO3 by 90° off-axis sputtering techniques. X-ray diffraction and transmission electron microscopy experiments reveal that the films are single crystals of c-axis 4H structures with an inplane epitaxial arrangement of BaRuO3 [2110] // SrTiO3 [110]. Smooth multilayer growth has been observed in these films with a step height equaling the size of half unit cell. In-plane resistivity of the films is metallic, with a room temperature value of about 810µΩ-cm and slightly curved temperature dependence. Their magnetic susceptibility is paramagnetic. The metastable layered compounds can be very useful for understanding new solid-state phenomena and novel device applications.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

The Precipitation of Si in AlCuSi Thin Films

1973 ◽  
Vol 31 ◽  
pp. 34-35 ◽  
Author(s):  
R. M. Anderson
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Heat Treatment ◽  
Solid Solution ◽  
Integrated Circuit ◽  
Copper Film ◽  
Solution Concentration ◽  
X Ray ◽  
Silicon Thin Films ◽  
Before And After

Aluminum-copper-silicon thin films have been considered as an interconnection metallurgy for integrated circuit applications. Various schemes have been proposed to incorporate small percent-ages of silicon into films that typically contain two to five percent copper. We undertook a study of the total effect of silicon on the aluminum copper film as revealed by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and ion microprobe techniques as a function of the various deposition methods.X-ray investigations noted a change in solid solution concentration as a function of Si content before and after heat-treatment. The amount of solid solution in the Al increased with heat-treatment for films with ≥2% silicon and decreased for films <2% silicon.

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