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Author

Ross E. Muenchausen

Other affiliations: Lucideon, University of New Mexico
Bio: Ross E. Muenchausen is an academic researcher from Los Alamos National Laboratory. The author has contributed to research in topics: Thin film & Pulsed laser deposition. The author has an hindex of 31, co-authored 143 publications receiving 3561 citations. Previous affiliations of Ross E. Muenchausen include Lucideon & University of New Mexico.


Papers
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Journal ArticleDOI
TL;DR: Czochralski growth of cerium-doped Lu 1.8Y 0.2SiO5 (LYSO) from a 90/10 solution of Lu 2SiO 5 (LSO) and Y 2Si O 5 (YSO) is demonstrated in this paper.
Abstract: Czochralski growth of cerium-doped Lu1.8Y0.2SiO5 (LYSO) from a 90/10 solution of Lu2SiO5 (LSO) and Y2SiO5 (YSO) is demonstrated. The alloyed scintillator retains the favorable growth properties of YSO and the desirable physical and optical scintillator properties of LSO. Radioluminescence, thermally stimulated luminescence, optical absorption, and lifetime measurements confirm the equivalence of LYSO and LSO optical properties. Advantages of LYSO Czochralski growth relative to LSO include reduced melting point, less propensity for formation of crystalline inclusions, lower cost of starting material, and easier incorporation of cerium into the host lattice. This material offers an attractive alternative to LSO for scintillator applications.

213 citations

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TL;DR: In this article, the epitaxial (100)CeO2 thin films on LaAlO3, sapphire, and yttria-stabilized zirconia using pulsed laser deposition were demonstrated to be chemically and structurally compatible to the high temperature superconductor YBa2Cu3O7−δ (YBCO).
Abstract: We have prepared epitaxial (100)CeO2 thin films on LaAlO3, sapphire, and yttria‐stabilized zirconia using pulsed laser deposition. It is demonstrated in this letter that the CeO2 films are chemically and structurally compatible to the high‐temperature superconductor YBa2Cu3O7−δ (YBCO). Epitaxial YBCO films on CeO2/LaAlO3 had a zero resistance temperature and critical current density in a zero field of 90 K and 5.9×106 A/cm2 at 75 K, respectively. Furthermore, epitaxial multilayers of CeO2/YBCO were prepared. This work demonstrated that CeO2 is an excellent buffer layer material for the high‐temperature superconductors.

192 citations

Journal ArticleDOI
TL;DR: SrRuO3 thin films were deposited on (100) LaAlO3 using pulsed laser deposition as discussed by the authors, and the films were oriented normal to the substrate surface with a high degree of inplane orientation with respect to the major axes.
Abstract: SrRuO3 thin films were deposited on (100) LaAlO3 using pulsed laser deposition. The films were (001) oriented normal to the substrate surface with a high degree of in‐plane orientation with respect to the substrate’s major axes. An ion beam minimum yield of 2.5% was obtained for the films, indicating high crystallinity. The films exhibited metallic behavior with a room temperature resistivity of ∼200 mW cm. A kink in the resistivity, corresponding to a ferromagnetic phase transition, was observed at ∼160 K. It was found that SrRuO3 is structurally and chemically compatible with the YaB2Cu3O7−d (YBCO) superconductors. High quality YBCO films were obtained on SrRuO3 LaAlO3. Multilayers of YBCO/SrRuO3 were successfully fabricated.

143 citations

Journal ArticleDOI
TL;DR: In this article, the authors studied the film growth mechanism as a function of deposition rate using pulsed laser deposition and observed the outgrowths nucleating at coalescence and proposed that certain defects related to the c-axis growth habit may be the fundamental cause of outgrowth formation.
Abstract: One problem with the growth of high quality c‐axis oriented YBa2Cu3O7−x films is the tendency of the film surface to become rough. We studied the film growth mechanism as a function of deposition rate using pulsed laser deposition. These films form by the classic nucleation and growth process; the thickness at which the nucleated islands coalesce increased with decreasing deposition rate. The film has pinholes prior to coalescence and nucleates outgrowths during coalescence. The outgrowths enlarge rapidly because they contain materials and crystallographic directions with growth rates faster than that of the c‐axis film. A smooth surface is obtained if the substrate temperature and deposition rate are chosen such that coalescence is just completed at the final film thickness. We observed the outgrowths nucleating at coalescence and propose that certain defects, related to the c‐axis growth habit, may be the fundamental cause of outgrowth formation. Outgrowths have not been observed in a‐axis films. Outgrowths are easily confused with the particulate deposition problem associated with laser deposition. In these experiments, the particulate problem was essentially eliminated by using freshly polished targets for each run.

138 citations

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TL;DR: In this article, a broad angular distribution was observed for XeCl laser ablation plumes used in the deposition of YBa2Cu3O7−δ thin films.
Abstract: Broad angular distributions have been observed for XeCl laser ablation plumes used in the deposition of YBa2Cu3O7−δ thin films. Distributions (inferred from film thickness) and film stoichiometry were measured as a function of laser fluence, beam shape, and oxygen pressure. Parallel to the long axis of the laser spot, plumes exhibited a cos3.5(θ) spread and composition varied with angle; in the perpendicular direction, more diffuse [cos1.5(θ)] plume distributions were associated with stoichiometric deposition. The observed phenomena are consistent with formation of a Knudsen layer near the target surface.

131 citations


Cited by
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TL;DR: In this paper, a comprehensive investigation of the thermo-dynamic stability of binary oxides in contact with silicon at 1000 K was conducted, including those involving ternary phases.
Abstract: Using tabulated thermodynamic data, a comprehensive investigation of the thermo-dynamic stability of binary oxides in contact with silicon at 1000 K was conducted. Reactions between silicon and each binary oxide at 1000 K, including those involving ternary phases, were considered. Sufficient data exist to conclude that all binary oxides except the following are thermodynamically unstable in contact with silicon at 1000 K: Li2O, most of the alkaline earth oxides (BeO, MgO, CaO, and SrO), the column IIIB oxides (Sc2O3, Y2O3, and Re2O3, where Re is a rare earth), ThO2, UO2, ZrO2, HfO2, and Al2O3. Of these remaining oxides, sufficient data exist to conclude that BeO, MgO, and ZrO2 are thermodynamically stable in contact with silicon at 1000 K. Our results are consistent with reported investigations of silicon/binary oxide interfaces and identify candidate materials for future investigations.

1,276 citations

Journal ArticleDOI
TL;DR: In this article, the authors describe the properties of the triangular flux-line lattice (FLL), which is more or less perturbed by material inhomogeneities that pin the flux lines, and also by thermal fluctuations.
Abstract: Magnetic flux can penetrate a type-II superconductor in the form of Abrikosov vortices (also called flux lines, flux tubes, or fluxons) each carrying a quantum of magnetic flux phi 0=h/2e. These tiny vortices of supercurrent tend to arrange themselves in a triangular flux-line lattice (FLL), which is more or less perturbed by material inhomogeneities that pin the flux lines, and in high-Tc superconductors (HTSCs) also by thermal fluctuations. Many properties of the FLL are well described by the phenomenological Ginzburg-Landau theory or by the electromagnetic London theory, which treats the vortex core as a singularity. In Nb alloys and HTSCs the FLL is very soft mainly because of the large magnetic penetration depth lambda . The shear modulus of the FLL is c66~1/ lambda 2, and the tilt modulus c44(k)~(1+k2 lambda 2)-1 is dispersive and becomes very small for short distortion wavelengths 2 pi /k<< lambda . This softness is enhanced further by the pronounced anisotropy and layered structure of HTSCs, which strongly increases the penetration depth for currents along the c axis of these (nearly uniaxial) crystals and may even cause a decoupling of two-dimensional vortex lattices in the Cu-O layers. Thermal fluctuations and softening may `melt` the FLL and cause thermally activated depinning of the flux lines or ofthe two-dimensional `pancake vortices` in the layers. Various phase transitions are predicted for the FLL in layered HTSCs. Although large pinning forces and high critical currents have been achieved, the small depinning energy so far prevents the application of HTSCs as conductors at high temperatures except in cases when the applied current and the surrounding magnetic field are small.

866 citations

Journal ArticleDOI
TL;DR: The literature on 4f n ↔4f n −1 5d transitions of the trivalent lanthanides in inorganic compounds has been collected as mentioned in this paper from critically analyzing fd-excitation, absorption, reflection and df-emission spectra, values for the spectroscopic red shift of 5d levels and the stokes shift were determined.

853 citations

Journal ArticleDOI
TL;DR: In this paper, the recent developments and trends in combustion science towards the synthesis of nanomaterials are discussed, and different modifications made to conventional combustion approaches for preparation of nano-materials are critically analyzed.
Abstract: The recent developments and trends in combustion science towards the synthesis of nanomaterials are discussed. Different modifications made to conventional combustion approaches for preparation of nanomaterials are critically analyzed. Special attention is paid to various applications of combustion synthesized nanosized products.

842 citations

Journal ArticleDOI
TL;DR: This Review focuses on the analysis of new approaches and results in the field of solution combustion synthesis (SCS) obtained during recent years, emphasizing the chemical mechanisms that are responsible for rapid self-sustained combustion reactions.
Abstract: Solution combustion is an exciting phenomenon, which involves propagation of self-sustained exothermic reactions along an aqueous or sol–gel media. This process allows for the synthesis of a variety of nanoscale materials, including oxides, metals, alloys, and sulfides. This Review focuses on the analysis of new approaches and results in the field of solution combustion synthesis (SCS) obtained during recent years. Thermodynamics and kinetics of reactive solutions used in different chemical routes are considered, and the role of process parameters is discussed, emphasizing the chemical mechanisms that are responsible for rapid self-sustained combustion reactions. The basic principles for controlling the composition, structure, and nanostructure of SCS products, and routes to regulate the size and morphology of the nanoscale materials are also reviewed. Recently developed systems that lead to the formation of novel materials and unique structures (e.g., thin films and two-dimensional crystals) with unusual...

841 citations