Search

The interface between the Al bottom contact layer and Si substrates in Al based Josephson junctions is believed to have a significant effect on the noise observed in Al based superconducting devices. We have studied the atomic structure of it by transmission electron microscopy. An amorphous layer with a thickness of ∼5 nm was found between the bottom Al electrode and HF-treated Si substrate. It results from intermixing between Al, Si, and O. We also studied the chemical bonding states among the different species using energy loss near edge structure. The observations are of importance for the understanding of the origin of decoherence mechanisms in qubits based on these junctions. [ABSTRACT FROM AUTHOR]

An interaction layer is found at the Al/SiO2 interface in Al/AlOx/Al tunnel junctions grown on SiO2 substrates. The amorphous intermixing layer has an average thickness of about 5 nm. We present the detailed structure of this interfacial layer as determined by transmission electron microscopy. The layer contains alumina with aluminum being octahedrally coordinated according to electron energy loss spectroscopy analysis rather than tetrahedrally coordinated, where the latter coordination is the most common type in amorphous alumina. Depth profiles of the Al-O and Si-O bonding characteristics were also investigated using energy loss near edge structure. [ABSTRACT FROM AUTHOR]

Presents a study to characterize Sr-deficient and stoichiometric epitaxial (001) SrTiO3 films, deposited on (110) rhombohedral LaA1O3 substrates by radio frequency (rf) magnetron sputtering. Utilization of high-resolution transmission electron microscopy; Details on methodology used to conduct study; Indication of findings; Discussion on results.

Reports on thin transparent tin oxide films doped with oxygen vacancies, antimony, fluorine or molybdenum. Experimental setup for the preparation of the films; Process optimization for optical and electrical properties; Analysis of the optical data; Film characterization with x-ray diffraction and transmission electron microscopy.

Provides information on a study which examined the growth of high quality superconducting films YBa[sub2]Cu[sub3]O[sub7-δ] on yttrium zirconium oxide substrates. Application of transmission electron microscopy; Results and discussion; Conclusions.

Abstract: Tool degradation may be significantly different depending on small variations in chemical compositions of the workpiece material. The present study is an in-depth microstructure investigation of worn low content polycrystalline cubic boron nitride tool materials after dry hard turning of steels with low and high sulphur contents. The results illustrate the important role of sulphur content on the degradation of the crater zone. Sulphides tend to adhere on the wear surface and form layers that protect the tool from workpiece ingress. In the absence of sulphides in the workpiece material, no protective layer can form and iron compounds make their way into the tool microstructure already at lower cutting speeds (150m/min) and preferably attack cBN grains compared to Ti(C,N) grains. [Copyright &y& Elsevier]

Sr2RuO4/Sr3Ru2O7 eutectic system is investigated by transmission electron microscopy (TEM) and high angle annular dark field scanning TEM (STEM). The Sr2RuO4/Sr3Ru2O7 lamellar structure allows studying tunneling and proximity effects between spin-triplet superconductor Sr2RuO4 and metamagnetic normal metal Sr3Ru2O7. Our analyses reveal two typologies of interfaces within the eutectic: interfaces parallel to the growth direction are sharp and defect-free whereas interfaces perpendicular to the growth direction appear wavy and decorated with Ru precipitates. These results indicate that interfaces parallel to the growth direction are the best candidates for Sr2RuO4/Sr3Ru2O7 natural junctions to study the unusual superconductivity of Sr2RuO4. [ABSTRACT FROM AUTHOR]

Presents the characterization of YBa[sub 2]Cu[sub 3]O[sub 7-x]/CaRuO[sub 3]/YBa[sub 2]Cu[sub 3]O[sub 7-x] (YBCO) Josephson edge junctions. Use of the transmission electron microscopy; Observation of damages during the fabrication of the edges; Enhancement of Y[sub 2]O[sub 3] particle nucleation; Importance of the YBCO edge morphology.

Abstract: Titanium carbide (TiC) coatings for tribological applications were deposited on high speed steel. Several coatings with different titanium to carbon ratio were deposited by means of physical vapour deposition in which titanium was evaporated and carbon was sputtered. The coatings were characterised using analytical electron microscopy. It was observed that the change in titanium to carbon ratio significantly changed the microstructure of the coatings. The low carbon containing coatings consisted of columnar grains exhibiting a preferred crystallographic orientation whereas the coating with highest carbon content consisted of randomly ordered TiC grains in an amorphous carbon matrix. Energy filtered transmission electron microscopy revealed a change in Ti/C ratio as the distance from the substrate increased. The titanium to carbon ratio was observed to increase with distance from the substrate until a stable level was reached. This is due to a variation in the titanium evaporation during the early stages of film growth. This change of the titanium to carbon ratio affected the columnar growth in the initial stage of coating growth for the coatings with low carbon content. [Copyright &y& Elsevier]

Abstract: The local effect of wear on the microstructure of a commercial low content Polycrystalline Cubic Boron Nitride (PCBN) tool material, with ∼55vol% cBN in a Ti(C,N)-matrix, has been investigated. The PCBN tool was used in dry hard turning of a case hardened steel. A crater developed on the rake face of the tool edge and the microstructure of this area has been studied in detail using Scanning Electron Microscopy (SEM) with Energy-Dispersive X-ray analysis and Transmission Electron Microscopy (TEM) with Electron Energy-Loss Spectroscopy and Energy Filtered TEM. A lift-out technique in a Focused Ion Beam/SEM instrument was used to produce thin foil specimens, <80nm in thickness. This technique provided the possibility to produce specimens from a specific location with sub-micron resolution. In this case, specimens were taken from across the rake face of the worn PCBN tool. The spatial resolution was substantially improved by using thin foils and it was possible to investigate the degraded microstructure down to the nanometre scale. The results show an adherent layer smearing the crater on the rake face of the PCBN tool cutting edge. Closer investigation of this layer reveals an inner layered structure with some characteristic features. This layer consists of elements from the workpiece material. The tool–adherent layer interface is smooth, showing rounded, concave wear surfaces of micron-sized cBN instead of the original flat grain surfaces. Larger Fe-rich areas are found which are oxidised on the surface, sometimes containing smaller amounts of Cr and Ni. Mn and S are found as larger, often elongated areas primarily close to the tool–adherent layer interface. The dominating degrading mechanism appears to be chemical degradation. The detailed microstructure of the tool–adherent layer interface and the adherent layer is presented. [Copyright &y& Elsevier]

Abstract: The microstructure of silver-containing indium tin oxide (ITO) films, deposited by sequential reactive direct current (DC) magnetron sputtering of ITO and Ag, was investigated by transmission electron microscopy (TEM) with selected area electron diffraction, high resolution TEM, energy dispersive spectroscopy, and energy-filtering TEM (EFTEM). All films had a columnar structure with (222) texture. The silver additive did not alter the ITO grain orientation, even though the columnar size of the ITO grains was decreased slightly when the silver content was increased. Nanoparticles of silver, with sizes ranging from 2 to 5 nm, were distributed in layers, as demonstrated by EFTEM using the Ag M4,5 peak. The influence of the silver deposit on the microstructure and properties of the ITO films is discussed. [Copyright &y& Elsevier]