Gmr Effect and Properties of CoAg Granular Films Formed by Implantation with a Metal Vapor Vacuum Arc Ion Source

1999 ◽  
Vol 577 ◽  
Author(s):  
S.P. Wong ◽  
M.F. Chiah ◽  
W.Y. Cheung ◽  
N. Ke ◽  
J.B. Xu ◽  
...  
Keyword(s):  
Temperature Variation ◽  
Giant Magnetoresistance ◽  
Rutherford Backscattering Spectrometry ◽  
Metal Vapor ◽  
Ion Source ◽  
Vacuum Arc ◽  
Granular Films ◽  
Force Microscopy ◽  
Domain Structures ◽  
Sputter Deposited

ABSTRACTCobalt-silver granular thin films were formed by Co implantation into Ag using a metal vapor vacuum arc (MEVVA) ion source. The magnetic field dependence and the temperature variation of the giant magnetoresistance (GMR) effect and their relation with the processing conditions were studied and discussed in conjunction with results of Rutherford backscattering spectrometry, atomic force microscopy, magnetic force microscopy (MFM), and SQUID measurements. Anomalous temperature dependence of the coercive field Hc in the perpendicular-to-film direction determined from GMR measurements was observed for some samples. For one sample, Hc shows a maximum value at around 240K and decreases with decreasing temperature from 240K to 20K. The temperature variation of the magnetization M of this sample exhibits a minimum. The maximum in the Hc-T curve corresponds well with the minimum in the M-T curve. The M-T curve suggests that there is more than one magnetic phase present in this sample. The domain structures of the implanted granular films as revealed by MFM images exhibit very different features compared with those of sputter deposited CoAg granular films.

CHARACTERIZATION OF ta-C AND GRANULAR Co-C FILMS PREPARED BY PULSED FILTERED VACUUM ARC DEPOSITION

2000 ◽  
Vol 14 (02n03) ◽  
pp. 321-332 ◽  
Author(s):  
S. P. WONG ◽  
H. WANG ◽  
N. KE ◽  
W. Y. CHEUNG ◽  
M. F. CHIAH ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Electrical Transport ◽  
Annealing Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Magnetic Measurements ◽  
Perpendicular Magnetic Anisotropy ◽  
Vacuum Arc ◽  
Electrical Measurements ◽  
Force Microscopy ◽  
Domain Structures

A pulsed filtered vacuum are deposition system was used to prepare ta-C thin films and granular Co-C films. The ta-C films prepared at various substrate bias voltages were characterized using Raman spectroscopy and spectroscopic ellipsometry of which the results confirmed that these ta-C films exhibit high sp 3 fraction of over 80%. The composition of the granular Co-C films prepared by the same system was determined by non-Rutherford backscattering spectrometry. The properties of these Co-C Films, as deposited and after vacuum annealing at various temperatures, were studied using Raman spectroscopy, electrical measurements, magnetic measurements by a SQUID magnetometer, atomic force microscopy and magnetic force microscopy. It was found that the dependence of the Raman spectra of these films on annealing temperature was associated with the formation and dissociation of a cobalt carbide phase and the graphitization of amorphous carbon. The magnetic properties showed complicated composition and annealing temperature dependence. The optimum annealing temperature for the maximum coercivity was found to depend on the composition of the film. For a film of Co 65 C 35 after annealing at 623K in vacuum for one hour, the coercivity was measured to be 460 Oe at 300K and 1380 Oe at 3K. Clear MFM images of the domain structures were observed for films after annealing at sufficiently high temperature, showing that there was perpendicular magnetic anisotropy in these films. A nearly-temperature-independent electrical resistance in the range from 20K to 300K was also observed. A more detailed analysis indicated that the low temperature electrical transport is consistent with a theory for granular metal films.

Growth and Characterization of Erbium Silicides Synthesized by Metal Vapor Vacuum Arc Ion Implantation

2000 ◽  
Vol 647 ◽  
Author(s):  
X. W. Zhang ◽  
W. Y. Cheung ◽  
S. P. Wong
Keyword(s):  
Rutherford Backscattering Spectrometry ◽  
Metal Vapor ◽  
Beam Current ◽  
Ion Source ◽  
Vacuum Arc ◽  
Beam Current Density ◽  
Metal Vapour ◽  
Sputtering Yield ◽  
Substrate Temperatures

AbstractErbium atoms were implanted into p-type Si (111) wafers at an extraction voltage of 60 kV to doses ranging from 5×1016 to 2×1017 cm−2 using a metal vapour vacuum arc (MEVVA) ion source. The implantation was performed with beam current densities from 3 to 26 µA/cm2 corresponding to substrate temperatures ranging from 85 to 245°C. The characterization of the as-implanted and annealed samples was performed using Rutherford backscattering spectrometry, atomic force microscopy and x-ray diffraction. To determine the sputtering yield, masked implantation experiments were performed so that the thickness of the sputtered layer at different substrate temperatures can be obtained directly by an α-step surface profiler. The results showed that ErSi2-xwas directly formed by MEVVA implantation when the substrate temperature was higher than about 160°C. The effects of the implant dose and the beam current density on the retained dose, the sputtering yield and the surface morphology of the implanted samples were also studied.

Afm Study of Surface Morphology of High Dose Co Implanted Si with A Mevva Ion Source

1995 ◽  
Vol 396 ◽  
Author(s):  
Qicai Peng ◽  
S.P. Wong ◽  
J.B. Xu ◽  
I.H. Wilson
Keyword(s):  
Surface Morphology ◽  
Metal Vapor ◽  
Ion Source ◽  
Vacuum Arc ◽  
Root Mean Square Roughness ◽  
High Dose ◽  
Abrupt Increase ◽  
Force Microscopy ◽  
Atomic Force ◽  
Substrate Temperatures

AbstractThe surface morphology of high dose Co implanted Si has been studied by atomic force microscopy. The Co implantation was performed using a metal vapor vacuum arc (MEVVA) ion source at an extraction voltage of 60 or 70 kV to a dose of 2×l017 or 4×l017 ions cm-2 at substrate temperatures Ts ranging from 210°C to 700°C. When Ts is less than about 600°C, the surface morphology of the implanted samples shows largely similar features of densely distributed narrow asperities. However, for the sample with Ts of 700°C, the surface morphology is significantly different and shows hillocks of much larger size. It is also found that when other parameters are fixed, for Ts less than about 600°C, the root-mean-square roughness Rrms increases exponentially with 7^, from the subnanometer scale to several nanometers. But for the sample with Ts of 700°C, there is an abrupt increase in Rrms to 35 nm. The variation of the surface morphology with other parameters is also discussed.

Performance of a high‐current metal vapor vacuum arc ion source

1990 ◽  
Vol 61 (12) ◽  
pp. 3775-3782 ◽  
Author(s):  
Hiroshi Shiraishi ◽  
Ian G. Brown
Keyword(s):  
Metal Vapor ◽  
Ion Source ◽  
Vacuum Arc ◽  
High Current

Study on the Dopedβ-FeSi 2 Obtained by Metal Vapor Vacuum Arc Ion Source Implantation and Post-Annealing

2002 ◽  
Vol 730 ◽  
Author(s):  
Shuangbao Wang ◽  
Hong Liang ◽  
Peiran Zhu
Keyword(s):  
Metal Vapor ◽  
Ion Source ◽  
Vacuum Arc ◽  
Post Annealing ◽  
Strong Current ◽  
Xrd Patterns ◽  
Fe Ions

Abstractβ-FeSi2 was firstly formed by implanting Si wafers with Fe ions at 50 kV to a dose of 5×1017/cm2in a strong current Metal Vapor Vacuum Arc (MEVVA) implanter. Secondly, Ti implantation was performed on these Fe as-implanted samples. The Fe + Ti implanted samples were furnace annealed in vacuum at temperatures ranging from 650 to 975°C. The XRD patterns of the annealed samples correspond to β-FeSi2 structure (namely β-Fe(Ti)Si2). When annealing was done above 1050°C, the β-Fe(Ti)Si2 transformed into α-Fe(Ti)Si2. This implies that introducing Ti stabilizes the β-FeSi2 phase. Resistance measurements were also performed.

Effects of a Large Content of Yttrium Doping on Microstructure and Magnetostriction of Fe83Ga17 Alloy

2019 ◽  
Vol 288 ◽  
pp. 27-36
Author(s):  
Li Juan Zhao ◽  
Xiao Tian ◽  
Zhan Quan Yao ◽  
Xuan Zhao ◽  
Ojiyed Tegus
Keyword(s):  
Magnetic Domain ◽  
Melting Furnace ◽  
Optical Microscope ◽  
Vacuum Arc ◽  
Force Microscopy ◽  
Domain Structures ◽  
Arc Melting ◽  
Bcc Structure ◽  
Magnetostriction Coefficient ◽  
Surface Morphologies

As-cast (Fe0.83Ga0.17)100-xYx (x=0, 3, 6 and 9) alloys were prepared by non-consumable vacuum arc melting furnace under a protective argon atmosphere. The crystal structures and surface morphologies of the alloys were studied by X-ray diffraction (XRD), optical microscope (OM) and scanning electron microscopy (SEM), combined with energy dispersive spectroscopy (EDS), respectively. The surface domain structures were observed by atomic force microscopy (AFM). The magnetostriction coefficients of the alloys were measured by strain gauging method. The results showed that the as-cast Fe83Ga17 alloy was composed only of a single phase of A2 with bcc structure, whereas the ternary Fe-Ga-Y alloys contain multiphase structure, besides the A2 phase, (FeGa)17Y1.76 new phases are observed as well, and an elemental yttrium phase appeared when the yttrium content increased to x=6 and x=9. Doping with yttrium have an effect on the change of magnetic domain structure of the binary alloy. With increasing x, the magnetostriction coefficient of the (Fe0.83Ga0.17)100-xYx alloys decreased sharply. The minimum magnetostriction coefficient is reduced to 12 ppm at the magnetic field of 426kA/m when x=9.

scholarly journals Formation of Buried Epitaxial Si-Ge Alloy Layers in Si Crystal by High Dose Ge ION Implantation

1991 ◽  
Vol 235 ◽  
Author(s):  
Kin Man Yu ◽  
Ian G. Brown ◽  
Seongil Im
Keyword(s):  
Ion Implantation ◽  
Single Crystal ◽  
Lattice Mismatch ◽  
Solid Phase ◽  
Metal Vapor ◽  
Ion Source ◽  
Vacuum Arc ◽  
High Dose ◽  
Solid Phase Epitaxy ◽  
Ion Channeling

ABSTRACTWe have synthesized single crystal Si1−xGex alloy layers in Si <100> crystals by high dose Ge ion implantation and solid phase epitaxy. The implantation was performed using the metal vapor vacuum arc (Mevva) ion source. Ge ions at mean energies of 70 and 100 keV and with doses ranging from 1×1016 to to 7×1016 ions/cm2 were implanted into Si <100> crystals at room temperature, resulting in the formation of Si1−xGex alloy layers with peak Ge concentrations of 4 to 13 atomic %. Epitaxial regrowth of the amorphous layers was initiated by thermal annealing at temperatures higher than 500°C. The solid phase epitaxy process, the crystal quality, microstructures, interface morphology and defect structures were characterized by ion channeling and transmission electron microscopy. Compositionally graded single crystal Si1−xGex layers with full width at half maximum ∼100nm were formed under a ∼30nm Si layer after annealing at 600°C for 15 min. A high density of defects was found in the layers as well as in the substrate Si just below the original amorphous/crystalline interface. The concentration of these defects was significantly reduced after annealing at 900°C. The kinetics of the regrowth process, the crystalline quality of the alloy layers, the annealing characteristics of the defects, and the strains due to the lattice mismatch between the alloy and the substrate are discussed.

Solid Phase Epitaxy of Implanted Si-Ge-C Alloys

1995 ◽  
Vol 388 ◽  
Author(s):  
Xiang Lu ◽  
Nathan W. Cheung
Keyword(s):  
Lattice Mismatch ◽  
Solid Phase ◽  
Metal Vapor ◽  
High Dose Rate ◽  
Ion Source ◽  
Vacuum Arc ◽  
High Dose ◽  
Solid Phase Epitaxy ◽  
Cross Sectional ◽  
Rutherford Back Scattering

AbstractSi1-x-yGexCy/Si heterostuctures were formed on Si (100) surface by Ge and C implantation with a high dose rate MEtal - Vapor Vacuum arc (MEVVA) ion source and subsequent Solid Phase Epitaxy (SPE). after thermal annealing in the temperature range from 600 °C to 1200 °C, the implanted layer was studied using Rutherford Back-scattering Spectrometry (RBS), cross-sectional High Resolution Transmission Electron Microscopy (HRTEM) and fourbounce X-ray Diffraction (XRD) measurement. Due to the small lattice constant and wide bandgap of SiC, the incorporation of C into Si-Ge can provide a complementary material to Si-Ge for bandgap engineering of Si-based heterojunction structure. Polycrystals are formed at temperature at and below 1000 °C thermal growth, while single crystal epitaxial layer is formed at 1100 °C and beyond. XRD measurements near Si (004) peak confirm the compensation of the Si1-x Gex lattice mismatch strain by substitutional C. C implantation is also found to suppress the End of Range (EOR) defect growth.

Electron-beam enhancement of the metal vapor vacuum arc ion source

2002 ◽  
Vol 92 (5) ◽  
pp. 2884-2889 ◽  
Author(s):  
V. A. Batalin ◽  
A. S. Bugaev ◽  
V. I. Gushenets ◽  
A. Hershcovitch ◽  
B. M. Johnson ◽  
...  
Keyword(s):  
Electron Beam ◽  
Metal Vapor ◽  
Ion Source ◽  
Vacuum Arc
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