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

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.

Author(s):  
P. P. Newcomer ◽  
L. M. Wang ◽  
M. L. Miller ◽  
R. C. Ewing

The Tl-Ba-Ca-Cu-O class of type-II high temperature superconductors (HTS) have Tc's as high as 125K. Although they have good critical current values, when a field is applied the weak pinning and consequent flow of magnetic vortices are a major impediment to the usefulness of these materials. Ion irradiation has been shown to enhance the pinning. High quality single crystals, as determined with x-ray precession and HRTEM, with sharp HTS Meissner signals, were irradiated with 1.5 MeV Kr+ and Xe+ ions using the HVEM-Tandem facility at Argonne National Laboratory. Ion beam microstructural modification was studied in-situ using electron diffraction and after irradiation using HRTEM and nano-beam EDS on Tl-1212 and Tl-2212 (numbers designate the stoichiometry Tl-Ba- Ca-Cu-O) single-crystal HTS. After irradiation, microstructure was studied using the JEOL 2010 in the Earth and Planetary Science Department at the University of New Mexico in order to characterize the resulting irradiation-induced nano-size precipitates.


1989 ◽  
Vol 157 ◽  
Author(s):  
O. Meyer ◽  
J. Geerk ◽  
T. Kroner ◽  
Q. Li ◽  
G. Linker ◽  
...  

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.


Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.


2018 ◽  
Author(s):  
C.S. Bonifacio ◽  
P. Nowakowski ◽  
M.J. Campin ◽  
M.L. Ray ◽  
P.E. Fischione

Abstract Transmission electron microscopy (TEM) specimens are typically prepared using the focused ion beam (FIB) due to its site specificity, and fast and accurate thinning capabilities. However, TEM and high-resolution TEM (HRTEM) analysis may be limited due to the resulting FIB-induced artifacts. This work identifies FIB artifacts and presents the use of argon ion milling for the removal of FIB-induced damage for reproducible TEM specimen preparation of current and future fin field effect transistor (FinFET) technologies. Subsequently, high-quality and electron-transparent TEM specimens of less than 20 nm are obtained.


2011 ◽  
Vol 1354 ◽  
Author(s):  
Jean Paul Allain ◽  
Osman El-Atwani ◽  
Alex Cimaroli ◽  
Daniel L. Rokusek ◽  
Sami Ortoleva ◽  
...  

ABSTRACTIon-beam sputtering (IBS) has been studied as a means for scalable, mask-less nanopatterning of surfaces. Patterning at the nanoscale has been achieved for numerous types of materials including: semiconductors, metals and insulators. Although much work has been focused on tailoring nanopatterning by systematic ion-beam parameter manipulation, limited work has addressed elucidating on the underlying mechanisms for self-organization of multi-component surfaces. In particular there has been little attention to correlate the surface chemistry variation during ion irradiation with the evolution of surface morphology and nanoscale self-organization. Moreover the role of surface impurities on patterning is not well known and characterization during the time-scale of modification remains challenging. This work summarizes an in-situ approach to characterize the evolution of surface chemistry during irradiation and its correlation to surface nanopatterning for a variety of multi-components surfaces. The work highlights the importance and role of surface impurities in nanopatterning of a surface during low-energy ion irradiation. In particular, it shows the importance of irradiation-driven mechanisms in GaSb(100) nanopatterning by low-energy ions and how the study of these systems can be impacted by oxide formation.


1986 ◽  
Vol 141-143 ◽  
pp. 776-780 ◽  
Author(s):  
S. Ishino ◽  
N. Sekimura ◽  
K. Hirooka ◽  
T. Muroga

1995 ◽  
Vol 396 ◽  
Author(s):  
Charles W. Allen ◽  
Loren L. Funk ◽  
Edward A. Ryan

AbstractDuring 1995, a state-of-the-art intermediate voltage electron microscope (IVEM) has been installed in the HVEM-Tandem Facility with in situ ion irradiation capabilities similar to those of the HVEM. A 300 kV Hitachi H-9000NAR has been interfaced to the two ion accelerators of the Facility, with a spatial resolution for imaging which is nearly an order of magnitude better than that for the 1.2 MV HVEM which dates from the early 1970s. The HVEM remains heavily utilized for electron- and ion irradiation-related materials studies, nevertheless, especially those for which less demanding microscopy is adequate. The capabilities and limitations of this IVEM and HVEM are compared. Both the HVEM and IVEM are part of the DOE funded User Facility and therefore are available to the scientific community for materials studies, free of charge for non-proprietary research.


1999 ◽  
Vol 5 (S2) ◽  
pp. 914-915
Author(s):  
T. Kamino ◽  
T. Yaguchi ◽  
H. Matsumoto ◽  
H. Kobayashi ◽  
H. Koike

A method for site specific characterization of the materials using a dedicated focused ion beam(FIB) system and an analytical transmission electron microscope (TEM) was developed. Needless to say, in TEM specimen preparation using FIB system, stability of a specimen is quite important. The specimen stage employed in the developed FIB system is the one designed for high resolution TEM, and the specimen drift rate of the stage is less than lnm/min. In addition, FIB-TEM compatible specimen holder which allows milling of a specimen with the FIB system and observation of the specimen with the TEM without re-loading was developed. To obtain thin specimen from the area to be characterized correctly, confirmation of the area before final milling is needed. However, observation of cross sectional view in a FIB system is recommended because it causes damage by Ga ion irradiation. To solve this problem, we used a STEM unit as a viewer of FIB milled specimen.


1993 ◽  
Vol 209 (4) ◽  
pp. 421-427 ◽  
Author(s):  
Ashok Kumar ◽  
J. Narayan ◽  
Bijoy Patnaik

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