Ion Beam Modification of High-Tc Superconductors

1989 ◽  
Vol 157 ◽  
Author(s):  
O. Meyer ◽  
J. Geerk ◽  
T. Kroner ◽  
Q. Li ◽  
G. Linker ◽  
...  
Keyword(s):  
Structural Changes ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
Lattice Parameter ◽  
Ion Beam Modification ◽  
Radiation Induced ◽  
Htsc Thin Films ◽  
Property Changes ◽  
Induced Changes

ABSTRACTIon irradiation and implantation experiments of high temperature superconductors (HTSC) thin films resulted in many interesting effects. Among those are: (i) the superlinear increase of the resistivity, p, with ion fluence, φ, leading to a metal to insulator transformation, (ii) the large recovery above 150 K of the radiation induced changes of ρ and Tc observed in low temperature irradiation experiments, and (iii) the large structural changes such as the increase of the c-axis lattice parameter with φ, the radiation induced orthorhombic to tetragonal phase transition, and the amorphization. Displaced oxygen atoms play an important role for the observed property changes.

Stress and Intermixing in Epitaxial Ni(111)/Mo(110) Superlattices

2007 ◽  
Vol 264 ◽  
pp. 1-6 ◽  
Author(s):  
Gregory Abadias ◽  
Aurelien Debelle ◽  
Anny Michel ◽  
Christiane Jaouen
Keyword(s):  
Stress State ◽  
Stress Relaxation ◽  
Structural Changes ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Lattice Parameter ◽  
Growth Stress ◽  
Chemical Effect ◽  
Ion Beam Sputtering ◽  
Epitaxial Relationship

The stress state and intermixing in epitaxial Ni/Mo multilayers grown on (11 2 0) sapphire substrates are investigated using X-ray Diffraction (XRD). Two deposition techniques were used, namely ion beam sputtering (IBS) and magnetron sputtering (MS), to vary the energy of the deposited species. In both cases, high-quality superlattices with a Nishiyama-Wasserman epitaxial relationship Ni [110] (111) // Mo [001] (110) were obtained. The residual stress state appears rather complex, resulting from two contributions: a growth-stress whose magnitude and sign depend on growth conditions and coherency stresses of opposite signs in the two elemental sublayers (tensile for Ni and compressive for Mo). Post-growth ion irradiation at low fluences was used to induce structural changes in a controlled way. For the case of IBS, it resulted in partial stress relaxation, as the growth stress could be almost fully relaxed, while the coherency stresses remained unchanged. For the case of MS, a distinct behavior was found: a stress increase of the tensile component of Mo-sublayers was observed, while a stress reduction of the compressive component was noticed. We attribute this phenomenon to ion irradiation induced intermixing. For the Ni sublayers, this intermixing leads to a stress relaxation. The modeling of the stress evolution during ion irradiation was performed using a triaxial stress analysis which enabled us to determine the ‘stress-free and defect-free lattice parameter’, solely linked to chemical effect.

Ion Beam Modification of TI-Ba-Ca-Cu-O Type High Temperature Superconductors During Irradiation

1994 ◽  
Vol 373 ◽  
Author(s):  
P.P. Newcomer ◽  
L. M. Wang ◽  
B. Morosin
Keyword(s):  
High Temperature ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
Ion Beam Modification ◽  
Moiré Fringes ◽  
High Resolution Tem ◽  
20 Nm ◽  
Induced Crystallization

AbstractMicrostructural modification of high temperature superconductor (HTS) single-crystal plates of T1-1212 and T1-2212 (numbers designate the Tl/Ba/Ca/Cu cation ratio) was studied during 1.5 MeV Kr+ and Xe+ ion irradiation with in-situ electron diffraction and after ion irradiation with high resolution TEM (HRTEM). Similar in-situ temperature dependence effects are seen for both phases. During irradiations from 22K to 673K, an amorphous halo develops after very low ion dose or fluence (l.7X1012 ions/cm2). During irradiation at 100K and 300K, complete amorphization is obtained, while at 22K and ≥533K, the halo fades slightly and a polycrystalline ring pattern develops, indicating ion irradiation induced crystallization occurred. After a low ion dose (8.5XlO12ions/cm2) at 100K and 300K, HRTEM reveals amorphous regions 5 -20 nm in size which are not columnar and do not all penetrate the entire sample thickness. At 22K and ≥533K, Moire fringes and misoriented crystallites of cascade size are observed. The 4 - 6nm crystallites are thallium-rich.

scholarly journals Effect of Ion Irradiation on Nanoindentation Fracture and Deformation in Silicon Carbide

JOM ◽  
2021 ◽  
Author(s):  
Alexander J. Leide ◽  
Richard I. Todd ◽  
David E. J. Armstrong
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Residual Stresses ◽  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Resolution Electron ◽  
Radiation Induced ◽  
Compressive Residual Stresses

AbstractSilicon carbide is desirable for many nuclear applications, making it necessary to understand how it deforms after irradiation. Ion implantation combined with nanoindentation is commonly used to measure radiation-induced changes to mechanical properties; hardness and modulus can be calculated from load–displacement curves, and fracture toughness can be estimated from surface crack lengths. Further insight into indentation deformation and fracture is required to understand the observed changes to mechanical properties caused by irradiation. This paper investigates indentation deformation using high-resolution electron backscatter diffraction (HR-EBSD) and Raman spectroscopy. Significant differences exist after irradiation: fracture is suppressed by swelling-induced compressive residual stresses, and the plastically deformed region extends further from the indentation. During focused ion beam cross-sectioning, indentation cracks grow, and residual stresses are modified. The results clarify the mechanisms responsible for the modification of apparent hardness and apparent indentation toughness values caused by the compressive residual stresses in ion-implanted specimens.

Intrinsic stress and alloying effect in Mo/Ni superlattices: a comparison between ion beam sputtering and thermal evaporation

2005 ◽  
Vol 875 ◽  
Author(s):  
A. Debelle ◽  
G. Abadias ◽  
A. Michel ◽  
C. Jaouen ◽  
Ph. Guérin ◽  
...  
Keyword(s):  
Thermal Evaporation ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Lattice Parameter ◽  
Growth Stress ◽  
Intrinsic Stress ◽  
Ion Beam Sputtering ◽  
Beam Sputtering ◽  
Deposited Energy

AbstractEpitaxial Mo(110)/Ni(111) superlattices were grown on (1120) single-crystal sapphiresubstrates, by ion beam sputtering (IBS) and thermal evaporation (TE), in order to investigate the role of deposited energy on the interfacial mixing process observed in Mo sublayers. To separate intermixing and growth stress contributions, a careful and detailed characterization of the stress/strain state of both samples was performed by X-ray Diffraction (XRD). Non-equal biaxial coherency stresses are observed in both samples. For the IBS specimen, an additional source of stress, of hydrostatic type, due to growth-induced point defects, is present, resulting in a triaxial stress state. The use of ion irradiation to achieve a controlled stress relaxation can provide additional data and, as shown elsewhere, allows to obtain the stress-free lattice parameter a0 solely linked to chemical effects. For the TE sample, a standard biaxial analysis gives a0. In both samples, the a0 value is lower than the bulk lattice parameter, due to the presence of intermixed Mo(Ni) layers. However, the intermixing is larger in the sputtered Mo sublayers than in the thermal evaporated ones, putting forward the prime role of energy and/or momentum transfer occurring during energetic bombardment.

Application of Cluster Ion Beam Smoothing to SiC and YBCO Surfaces

1999 ◽  
Vol 585 ◽  
Author(s):  
D. Fathy ◽  
O. W. Holland ◽  
R. Liu ◽  
J. Wosik ◽  
W. K Chu
Keyword(s):  
Surface Topography ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
Cluster Ions ◽  
Microwave Surface Resistance ◽  
Average Roughness ◽  
Cross Sectional ◽  
Cluster Ion Beams ◽  
Cluster Ion

AbstractOptimization of the surface topography, especially in high-temperature superconductors (HTS) and silicon carbide is crucial for device processing. Surface smoothing in these materials was investigated using Gas Cluster Ion Beams (GCIB) capable of delivering cluster ions of ≥ 2000 Ar atoms with energies of up to 30keV. Examination of the surface topography after cluster-ion irradiation was done using cross-sectional transmission electron microscopy (TEM) and atomic force microscopy (AFM). The results indicate that typical as-deposited YBCO films on MgO substrates have an average roughness of the order of 40 nm, and interpeak distance between 300–600 nm. Application of GCIB to the surface planarization reduces the roughness to only 10 nm. Also power handling and microwave surface resistance of the YBCO film and its relationship to surface smoothness are reported. Similar observations using bulk SiC are discussed.

Structural Modifications in Thin Films Caused by Gamma Radiation

2005 ◽  
Vol 480-481 ◽  
pp. 13-20 ◽  
Author(s):  
Khalil Arshak ◽  
Olga Korostynska ◽  
John Henry
Keyword(s):  
Thin Films ◽  
Gamma Radiation ◽  
Structural Changes ◽  
X Ray Diffraction ◽  
Thermal Vacuum ◽  
X Ray ◽  
Structural Modifications ◽  
Thin Oxide Films ◽  
Radiation Induced ◽  
Induced Changes

This paper reports on the gamma radiation-induced changes in thin oxide films deposited by thermal vacuum technique. Structures of various oxides thin films, such as In2O3, SiO and TeO2 and their mixtures in different proportions were studied. The influence of gamma radiation on In2O3/SiO films has resulted in significant changes in the microstructure of this film. Some kind of agglomerations with variable sizes in the range 0.5-3 µm has occurred. After a dose of 8160 µSv an evidence of partial crystallisation was observed with X-ray diffraction. Structural changes in TeO2 thin film were explored by means of Raman spectroscopy. After they have been exposed to g- radiation, a strong peak appeared at 448.83 cm-1, indicating further transformation to g-TeO2 modification.

Effect of Cascade Remnants on Freely Migrating Defects in Cu -1 % Au Alloys

1995 ◽  
Vol 396 ◽  
Author(s):  
A. Iwase ◽  
L. E. Rehn ◽  
P. M. Baldo ◽  
L. Funk
Keyword(s):  
Heavy Ions ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Heavy Ion ◽  
The Other ◽  
Inert Gas ◽  
Heavy Ion Irradiation ◽  
Simultaneous Irradiation ◽  
Radiation Induced ◽  
Cu Ions

AbstractThe effects of cascade remnants on Freely Migrating Defects (FMD) were studied by measuring Radiation-Induced Segregation (RIS) in Cu-l%Au at 400°C during simultaneous irradiation with 1.5-MeV He and (400-800)-keV heavy ions (Ne, Ar or Cu). The large RIS observed during 1.5-MeV He-only irradiation was dramatically suppressed under simultaneous heavy ion irradiation. For Cu simultaneous irradiation, the suppression disappeared immediately after the Cu irradiation ceased, while for simultaneous inert gas (Ne or Ar) irradiation, the suppression persisted after the ion beam was turned off. These results demonstrate that the displacement cascades created by heavy ions introduce additional annihilation sites, which reduce the steady-state FMD concentrations. As the cascade remnants produced by Cu ions are thermally unstable at 400°C, the RIS suppression occurs only during simultaneous irradiation. On the other hand, the inert gas atoms which accumulate in the specimen apparently stabilize the cascade remnants, allowing the suppression to persist.

Defect Structure of Ion-Irradiated Amorphous SiO2

1997 ◽  
Vol 30 (5) ◽  
pp. 618-622 ◽  
Author(s):  
Y. Eyal ◽  
R. Evron ◽  
Y. Cohen
Keyword(s):  
Ion Irradiation ◽  
Chemical Properties ◽  
Atomic Displacement ◽  
Amorphous Sio2 ◽  
X Ray Scattering ◽  
Scattering Centers ◽  
Radiation Induced ◽  
Induced Changes ◽  
Physical And Chemical ◽  
And Chemical Properties

Uniformly enhanced small-angle X-ray scattering intensities of amorphous SiO2, measured following irradiation with 320 keV H+ and He+ beams, are shown to be correlated, irrespective of the incident ion, with the O and Si cumulative displacement yields. Damage by both beams originated primarily from nuclear stopping but, under H+-ion irradiation, contributions from ionization processes were significant as well. At low beam fluences, the irradiated structure is compatible with the presence of stable radiation-induced interstitial-like O and Si atoms and complementary O and Si vacancy-like sites. There is no evidence for recovery near room temperature of the modified structure to the pre-irradiated state or for formation of colloidal-size scattering centers, such as gas bubbles or voids. Thus, ion-irradiation-induced changes in physical and chemical properties of silica seem to be due to the effect of the preserved primary atomic displacement damage.

Microstructural Observation of Focused Ion Beam Modification of Ni Silicide/Si Thin Films

1996 ◽  
Vol 439 ◽  
Author(s):  
Miyoko Tanaka ◽  
Kazuo Furuya ◽  
Tetsuya Saito
Keyword(s):  
Structural Changes ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Dark Field ◽  
In Situ Tem ◽  
Si Substrate ◽  
Ion Beam Modification ◽  
Surrounding Matrix ◽  
Transmission Electron

AbstractFocused ion beam (FIB) irradiation of a thin Ni2Si layer deposited on a Si substrate was carried out and studied using an in-situ transmission electron microscope (in-situ TEM). Square areas on sides of 4 by 4 and 9 by 9 μm were patterned at room temperature with a 25keV Ga+-FIB attached to the TEM. The structural changes of the films indicate a uniform milling; sputtering of the Ni2Si layer and the damage introducing to the Si substrate. Annealing at 673 K results in the change of the Ni2Si layer into an epitaxial NiSi2 layer outside the FIB irradiated area, but several precipitates appear around the treated area. Precipitates was analyzed by energy dispersive X-ray spectroscopy (EDS). Larger amount of Ni than the surrounding matrix was found in precipitates. Selected area diffraction (SAD) patterns of the precipitates and the corresponding dark field images imply the formation of a Ni rich silicide. The relation between the FIB tail and the precipitation is indicated.

Conducting Polymer Films by Ion Implantation

1989 ◽  
Vol 154 ◽  
Author(s):  
P.H. Lu ◽  
R.A. Moody ◽  
I.H. Loh
Keyword(s):  
Ion Implantation ◽  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Ion Beam ◽  
Beam Current ◽  
Beam Current Density ◽  
Electrically Conductive ◽  
Energy Beam ◽  
Ion Beam Modification ◽  
Spin Resonance

AbstractInsulating polymeric sheets were made electrically conductive by ion implantation. The effects of implantation parameters, such as ion species, dose, energy, beam current density, and substrate temperature, on the resultant sheet resistivities were investigated. Surface structural changes of implanted polymers were evaluated by X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectroscopy (RBS), and Fourier transform infared spectroscopy (FTIR). Electron spin resonance (ESR) and temperature dependent resistivity measurements were performed to explore the conduction mechanisms of implanted polymers. The results indicate that ion beam modification of polymers proceeds via a similar mechanism as high temperature pyrolysis. The resultant carbon-enriched materials which can be described by the conducting grain model.

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