The Formation of High-Coercivity, Oriented, Nanophase Cobalt Precipitates in Al2O3 Single Crystals by Ion Implantation

1999 ◽  
Vol 581 ◽  
Author(s):  
S. Honda ◽  
F. A. Modine ◽  
T. E. Haynes ◽  
A. Meldrum ◽  
J. D. Budai ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Ion Implantation ◽  
Single Crystals ◽  
Data Storage ◽  
Magnetic Circular Dichroism ◽  
Surface Region ◽  
Magnetic Data ◽  
High Coercivity ◽  
Saturation Field ◽  
Near Surface

ABSTRACTIon-implantation and thermal-processing methods have been used to form nanophase magnetic precipitates of metallic cobalt that are embedded in the near-surface region of single crystals of Al2O3. The Co precipitates are isolated, single-crystal particles that are crystallographically oriented with respect to the host Al2O3 lattice. Embedded nanophase Co precipitates were formed by the implantation of Co+ at an energy of 140 keV and a dose of 8 × 1016 ions/cm2 followed by annealing in a reducing atmosphere. The implanted/annealed Co depth profile, particle size distributions and shapes, and the orientational relationship between the nanophase precipitates and the host crystal lattice were determined using RBS/channeling, transmission electron microscopy, and x-ray diffraction. Magneto-optical effects arising from Co precipitates formed in the near-surface region of Al2O3 were observed and characterized using magnetic circular dichroism. Magnetic properties of the Co-particle/host nanocomposites were investigated in the temperature range of 77 to 295 K in applied fields of up to 10 kG using a superconducting quantum interference device (SQUID) magnetometer. Implantation of the Co particles by Pt or Xe ions produced a large anisotropic increase in their coercivity. Accordingly, these magnetic nanoparticle systems may be of interest for magnetic data storage applications. Details of the magnetic properties of the Co/Al2O3 nanocomposites including their retentivity, coercivity, saturation field, and magnetic anisotropy are presented.

Controlling the Microstructure and Magnetic Properties of Ferromagnetic Nanocrystals Produced by Ion Implantation

2001 ◽  
Vol 703 ◽  
Author(s):  
K.S. Beaty ◽  
A. Meldrum ◽  
J.P. Franck ◽  
K. Sorge ◽  
J. R. Thompson ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Ion Implantation ◽  
Magnetic Circular Dichroism ◽  
Magnetic Hysteresis ◽  
Near Surface ◽  
Magnetic Elements ◽  
Transmission Electron ◽  
Wide Range ◽  
Co Nanoparticles

ABSTRACTIon implantation coupled with annealing is a versatile and flexible approach to creating ferromagnetic near-surface nanocomposites that represent a wide range of particle/host combinations. We have used ion implantation and thermal processing to create a layer of Co nanoparticles in a sapphire host that was subsequently irradiated with Xe, Pt, or Pb in order to systematically modify the magnetic properties of the composite. Transmission electron microscopy (reported in an accompanying paper in this volume) was used to carry out a detailed characterization of the microstructure of the resulting near-surface composites whose magnetic properties were determined using SQUID magnetometry or magnetic circular dichroism. These composites exhibit magnetic hysteresis with coercivities ranging from near zero (i.e., superparamagnetism) up to 1.2 kG - depending on the composition and microstructure. We also present the results of preliminary experiments in which we attempt to control the spatial distribution of magnetic elements within ion-implanted ferromagnetic nanocomposites. The results demonstrate methods for tailoring the magnetic properties of nanocomposites produced by ion implantation for specific applications.

Ion-Implantation/Annealing-Induced Precipitation of Nanophase Ferromagnetic Particles In Yttrium-Stabilized ZrO2

1998 ◽  
Vol 540 ◽  
Author(s):  
S. Honda ◽  
F.A. Modine ◽  
A. Meldrum ◽  
J.D. Budai ◽  
T.E. Haynes ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Magnetic Circular Dichroism ◽  
Critical Factor ◽  
Surface Region ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Near Surface ◽  
Annealing Conditions ◽  
Optical Effects ◽  
Processing Techniques

AbstractIon implantation and thermal processing techniques have been used to form embedded ferromagnetic nanophase precipitates and thereby create magneto-optically active near-surface regions on otherwise inactive materials. Ferromagnetic precipitates were formed by first implanting Fe+ or Ni− into Y0.15Zr0.85O1.93(YSZ) with an implant energy of 140 keV, a fluence of 8.0 × 1016 ions/cm2, and at a temperature of-189°C. After implantation, the specimens were annealed at temperatures ranging from 500 to 1100°C in several types of reducing atmospheres. X-ray diffraction and TEM analysis of the Fe- or Ni-implanted/annealed specimens revealed that crystallographically coherent precipitates of metallic α-Fe, magnetite (Fe3O4), or Ni could be formed in YSZ depending on the annealing conditions. In particular, the cooling rate was established as the critical factor that determined whether Fe or Fe3O4 precipitates were created. Magneto-optical effects arising from ferromagnetic precipitates of Fe, Fe3O4, and Ni in the near-surface region of YSZ were observed and characterized using magnetic circular dichroism (MCD). The magneto-optical response of the α-Fe, Fe3O4, and Ni precipitates was markedly different as indicated by the MCD-detected hysteresis curves. The precipitation mechanism, the chemical nature of the precipitates, and the particle-size distributions resulting from different annealing conditions were investigated and correlated with the precipitate magneto-optical properties.

The Effects of Ion Implantation on the Surface Features of Inconel 600

1985 ◽  
Vol 43 ◽  
pp. 288-289
Author(s):  
John D. Rubio
Keyword(s):  
Grain Boundary ◽  
Ion Implantation ◽  
Nuclear Power ◽  
Power Plants ◽  
Surface Region ◽  
Selective Dissolution ◽  
Boundary Region ◽  
Near Surface ◽  
Inconel 600 ◽  
Steam Generator Tubing

The degradation of steam generator tubing at nuclear power plants has become an important problem for the electric utilities generating nuclear power. The material used for the tubing, Inconel 600, has been found to be succeptible to intergranular attack (IGA). IGA is the selective dissolution of material along its grain boundaries. The author believes that the sensitivity of Inconel 600 to IGA can be minimized by homogenizing the near-surface region using ion implantation. The collisions between the implanted ions and the atoms in the grain boundary region would displace the atoms and thus effectively smear the grain boundary.To determine the validity of this hypothesis, an Inconel 600 sample was implanted with 100kV N2+ ions to a dose of 1x1016 ions/cm2 and electrolytically etched in a 5% Nital solution at 5V for 20 seconds. The etched sample was then examined using a JEOL JSM25S scanning electron microscope.

scholarly journals Al-driven peculiarities of local coordination and magnetic properties in single-phase Alx-CrFeCoNi high-entropy alloys

Nano Research ◽  
2021 ◽  
Author(s):  
Alevtina Smekhova ◽  
Alexei Kuzmin ◽  
Konrad Siemensmeyer ◽  
Chen Luo ◽  
Kai Chen ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Magnetic Circular Dichroism ◽  
Surface Region ◽  
Face Centered Cubic ◽  
X Rays ◽  
X Ray ◽  
High Entropy ◽  
X Ray Absorption ◽  
Absorption Edges

AbstractModern design of superior multi-functional alloys composed of several principal components requires in-depth studies of their local structure for developing desired macroscopic properties. Herein, peculiarities of atomic arrangements on the local scale and electronic states of constituent elements in the single-phase face-centered cubic (fcc)- and body-centered cubic (bcc)-structured high-entropy Alx-CrFeCoNi alloys (x = 0.3 and 3, respectively) are explored by element-specific X-ray absorption spectroscopy in hard and soft X-ray energy ranges. Simulations based on the reverse Monte Carlo approach allow to perform a simultaneous fit of extended X-ray absorption fine structure spectra recorded at K absorption edges of each 3d constituent and to reconstruct the local environment within the first coordination shells of absorbers with high precision. The revealed unimodal and bimodal distributions of all five elements are in agreement with structure-dependent magnetic properties of studied alloys probed by magnetometry. A degree of surface atoms oxidation uncovered by soft X-rays suggests different kinetics of oxide formation for each type of constituents and has to be taken into account. X-ray magnetic circular dichroism technique employed at L2.3 absorption edges of transition metals demonstrates reduced magnetic moments of 3d metal constituents in the sub-surface region of in situ cleaned fcc-structured Al0.3-CrFeCoNi compared to their bulk values. Extended to nanostructured versions of multicomponent alloys, such studies would bring new insights related to effects of high entropy mixing on low dimensions.

scholarly journals Microstructure and Mechanical Properties of Ti + N Ion Implanted Cronidur30 Steel

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 427 ◽  
Author(s):  
Jie Jin ◽  
Wei Wang ◽  
Xinchun Chen
Keyword(s):  
Mechanical Properties ◽  
Ion Implantation ◽  
Photoelectron Spectroscopy ◽  
Structural Modification ◽  
Surface Region ◽  
Grazing Incidence ◽  
Bearing Steel ◽  
Near Surface ◽  
X Ray ◽  
Ion Implanted

In this study, Ti + N ion implantation was used as a surface modification method for surface hardening and friction-reducing properties of Cronidur30 bearing steel. The structural modification and newly-formed ceramic phases induced by the ion implantation processes were investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and grazing incidence X-ray diffraction (GIXRD). The mechanical properties of the samples were tested by nanoindentation and friction experiments. The surface nanohardness was also improved significantly, changing from ~10.5 GPa (pristine substrate) to ~14.2 GPa (Ti + N implanted sample). The friction coefficient of Ti + N ion implanted samples was greatly reduced before failure, which is less than one third of pristine samples. Furthermore, the TEM analyses confirmed a trilamellar structure at the near-surface region, in which amorphous/ceramic nanocrystalline phases were embedded into the implanted layers. The combined structural modification and hardening ceramic phases played a crucial role in improving surface properties, and the variations in these two factors determined the differences in the mechanical properties of the samples.

Modification of The Near-Surface Region Of Al2O3 By Ion Implantation

1983 ◽  
Vol 24 ◽  
Author(s):  
C. W. White ◽  
G. C. Farlow ◽  
H. Naramoto ◽  
C. J. Mchargue ◽  
B. R. Appleton
Keyword(s):  
Mechanical Properties ◽  
Ion Implantation ◽  
Thermal Annealing ◽  
Structural Property ◽  
Surface Region ◽  
Impurity Incorporation ◽  
Near Surface ◽  
Implantation Damage ◽  
Property Changes

ABSTRACTPhysical and structural property changes resulting from ion implantation and thermal annealing of α-A12O3 are reviewed. Emphasis is placed on damage production during implantation, damage recovery during thermal annealing, and impurity incorporation during thermal annealing. Physical and structural property changes caused by ion implantation and annealing are correlated with changes in the mechanical properties.

Modification of the magnetic properties of longitudinal thin-film media by ion-beam irradiation

2001 ◽  
Vol 674 ◽  
Author(s):  
Jason D. Wright ◽  
Kannan M. Krishnan
Keyword(s):  
Thin Film ◽  
Magnetic Properties ◽  
Ion Implantation ◽  
Ion Beam ◽  
High Coercivity ◽  
Beam Irradiation ◽  
Ion Beam Irradiation ◽  
Patterned Media ◽  
Chromium Ion ◽  
Stencil Mask

ABSTRACTThe modification of conventional longitudinal recording media by ion-beam irradiation is of both scientific and technological interest. In particular, patterning by irradiation through a stencil mask at the 50 nm length scale may fulfill the promise of a commercially viable patterned media architecture. In this context, the magnetic properties and microstructural evolution of high-coercivity longitudinal thin film media were investigated after ion-beam irradiation. TRIM simulations were used to calculate the depth profiles and damage distributions as a function of energy and dose for carbon, nitrogen, and chromium ions and three different media (C, Cr, no capping layer). Corresponding implantations were carried out and hysteresis curves were measured using a vibrating sample magnetometer (VSM). Using chromium ion implantation at 20 keV, both remanence and coercivity were reduced to zero, i.e., rendering the ferromagnetic thin film paramagnetic, at doses as low as 1×1016 cm−2. For C+ implantation at 20 keV, remanence and coercivity were also reduced to varying extent up to doses of 5×1016 cm−2 after which further irradiation had no effect. Slight decreases in remanence and coercivity were observed for 20 keV N2+ irradiation. XRD measurements indicate that the hexagonal cobalt alloy phase remains intact after irradiation. The physical and magnetic domain structures at the surface were assessed by atomic force and magnetic force microscopy. Combined with the development of a suitable stencil mask, such chromium ion implantation can be used to develop a viable patterned media with nanoscale dimensions, consisting of locally defined ferromagnetic and paramagnetic regions. This work is in progress.

scholarly journals Structural, Dielectric and Magnetic properties of Yttrium doped Hematite Nanoparticle

2021 ◽  
Author(s):  
Vijay Kumar ◽  
Dharamvir Singh Ahlawat ◽  
Amrik Singh ◽  
Arun Kumar ◽  
Ompal Singh
Keyword(s):  
Health Care ◽  
Grain Size ◽  
Magnetic Properties ◽  
Rare Earth ◽  
Crystallite Size ◽  
Data Storage ◽  
Rare Earth Metals ◽  
Magnetic Data ◽  
Xrd Patterns ◽  
Rhombohedral Symmetry

Abstract Applicability of magnetic crystalline nanoparticles particularly in the diagnostic field of health care and magnetic data storage makes them highly important for various technological researches. Novel properties of prepared nanoparticles can be tuned with doping of rare earth metals. In the present research, Yttrium (Y) doped hematite nanocrystalline samples have been prepared at various compositions, Fe2 − 2xY2xO3 (x = 0.00, 0.02, 0.05, 0.08, 0.10) and magnetic properties are seen sensitive with dopants concentration. The variation in grain size from FE-SEM is found well collaborated with the crystallite size and strain determined by XRD measurements. Rietveld refinement of XRD patterns reveals the formation of rhombohedral symmetry with Rˉ3c space group of the samples. The dielectric and magnetic properties show wiggling behaviour with the concentration of doping metal. A shift towards weakly ferromagnetic conduct like behaviour has been confirmed with the doping of Y in hematite crystalline particles.

Effects of Silicon Ion Implantation upon Thin Gate Oxide Integrity

1992 ◽  
Vol 262 ◽  
Author(s):  
G. -S. Lee ◽  
J. -G. Park ◽  
S. -P. Choi ◽  
C. -H. Shin ◽  
Y. -B. Sun ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Dielectric Breakdown ◽  
Defect Density ◽  
Surface Region ◽  
Gate Oxide ◽  
Near Surface ◽  
Time Dependent Dielectric Breakdown ◽  
Thin Gate Oxide ◽  
Si Ion Implantation ◽  
Gate Oxide Integrity

ABSTRACTIn this study, using oxide breakdown voltage and time-dependent-dielectric breakdown measurements, thermal wave modulated reflectance and chemical etching/optical microscopy, we investigated effects of Si ion implantation upon formation of D-defects and thin gate oxide integrity. Our data show that addition of Si ion implantation with a dose of up to 1013 ions/cm2 improves oxide integrity if the implantation is done at a certain step just before sacrificial oxidation in the Mb DRAM process. However, no improvement in oxide integrity is observed when the same implantation is done on the virgin wafer surfaces at the start of the same Mb DRAM process. We discuss our hypothesis that the improvement in oxide integrity is due to a reduction in the D-defect density in the near-surface region of the wafer.

scholarly journals Optimum technological modes of ion implantation and subsequent annealing for formation of thin nanosized silicide films

2021 ◽  
Vol 264 ◽  
pp. 05037
Author(s):  
Ilkhom Bekpulatov ◽  
Ilkhom Turapov ◽  
Sevara Abraeva ◽  
Jakhongir Normuminov
Keyword(s):  
Electron Diffraction ◽  
Ion Implantation ◽  
Electron Spectroscopy ◽  
Surface Region ◽  
Low Energy ◽  
Subsequent Annealing ◽  
Metal Silicide ◽  
Slow Electron ◽  
Near Surface ◽  
Nanoscale Films

Using the methods of electron spectroscopy and slow electron diffraction, we studied the processes of the formation of nanosized metal silicide films in the near-surface region of Si (111) and Si (100) during low-energy implantation of Ba ions and alkaline elements. The optimal technological modes of ion implantation and subsequent annealing for the formation of thin nanoscale films of silicides were determined. The type of surface superstructures of thin silicide films has been established.

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