1,901 research outputs found

    Report / Institute fĂĽr Physik

    Get PDF
    The 2014 Report of the Physics Institutes of the Universität Leipzig presents a hopefully interesting overview of our research activities in the past year. It is also testimony of our scientific interaction with colleagues and partners worldwide. We are grateful to our guests for enriching our academic year with their contributions in the colloquium and within the work groups. The open full professorship in the Institute for Experimental Physics I has been filled with an outstanding candidate. We could attract Prof. Ralf Seidel from the University of Münster. He is an expert in molecular biophysics that complements the existing strength in cellular biophysics. Prof. Hollands could fill all positions of his ERC Starting Grant, so that the work on the project \"Quantum Fields and Curvature – Novel Constructive Approach via Operator Product Expansion\" is now running at full pace. Within the Horizon 2020 project LOMID \"Large Cost-effective OLED Microdisplays and their Applications\" (2015-2017) with eight European partners including industry the semiconductor physics group contributes with transparent oxide devices. A joint laboratory for single ion implantation was established between the Leibniz-Institute for Surface Modification (IOM) and the university under the guidance of Profs. Rauschenbach and Meijer. The EU IRSES Network DIONICOS \"Dynamics of and in Complex Systems\", a consortium of 6 European and 12 non-European partners, including sites in England, France and Germany as well as in Russia, Ukraine, India, the United States and Venezuela, started in February 2014. In the next four years the Leipzig node headed by Prof. Janke will profit from the numerous international contacts this network provides. With a joint project, Prof. Kroy and Prof. Cichos participate in the newly established priority research programme SPP 1726 \"Microswimmers\", which started with a kick-off workshop in October 2014. In 2014 the International Graduate College \"Statistical Physics of Complex Systems\" run by the computational physics group has commenced its third 3-years granting period funded by Deutsch-Französische Hochschule (DFH-UFA). Besides the main partner Université de Lorraine in Nancy, France, now also Coventry University, UK, and the Institute for Condensed Matter Physis of the National Academy of Sciences of Ukraine in Lviv, Ukraine, participate as associated partners. During the last week of September the TCO2014 conference \"Transparent Conductive Oxides – Fundamentals and Applications\" took place in honor of the 100th anniversary of the death of Prof. Dr. KarlW. Bädeker. In 1907 Karl Bädeker had discovered transparent conductive materials and oxides in Leipzig. About a hundred participants joined for many invited talks from international experts, intense discussion and new cooperations. At the end of November the by now traditional 15th nternational Workshop on Recent Developments in Computational Physics \"CompPhys14\" organized by Prof. Janke took place in Leipzig. Around 60 scientists from over 10 different countries exchanged ideas and discussed recent progress in several fields of computational physics. Work has successfully continued in the Centers of Excellence (Sonderforschungsbereiche) SFB 762 \"Functionality ofOxide Interfaces\" and SFB TRR 102 \"Polymers under Multiple Constraints: Restricted and Controlled Molecular Order and Mobility\" (just renewed for 2015-2019). Our activities and success are only possible with the generous support fromvarious funding agencies for which we are very grateful and which is individually acknowledged in the brief reports

    Report / Institute fĂĽr Physik

    Get PDF
    The 2014 Report of the Physics Institutes of the Universität Leipzig presents a hopefully interesting overview of our research activities in the past year. It is also testimony of our scientific interaction with colleagues and partners worldwide. We are grateful to our guests for enriching our academic year with their contributions in the colloquium and within the work groups. The open full professorship in the Institute for Experimental Physics I has been filled with an outstanding candidate. We could attract Prof. Ralf Seidel from the University of Münster. He is an expert in molecular biophysics that complements the existing strength in cellular biophysics. Prof. Hollands could fill all positions of his ERC Starting Grant, so that the work on the project \"Quantum Fields and Curvature – Novel Constructive Approach via Operator Product Expansion\" is now running at full pace. Within the Horizon 2020 project LOMID \"Large Cost-effective OLED Microdisplays and their Applications\" (2015-2017) with eight European partners including industry the semiconductor physics group contributes with transparent oxide devices. A joint laboratory for single ion implantation was established between the Leibniz-Institute for Surface Modification (IOM) and the university under the guidance of Profs. Rauschenbach and Meijer. The EU IRSES Network DIONICOS \"Dynamics of and in Complex Systems\", a consortium of 6 European and 12 non-European partners, including sites in England, France and Germany as well as in Russia, Ukraine, India, the United States and Venezuela, started in February 2014. In the next four years the Leipzig node headed by Prof. Janke will profit from the numerous international contacts this network provides. With a joint project, Prof. Kroy and Prof. Cichos participate in the newly established priority research programme SPP 1726 \"Microswimmers\", which started with a kick-off workshop in October 2014. In 2014 the International Graduate College \"Statistical Physics of Complex Systems\" run by the computational physics group has commenced its third 3-years granting period funded by Deutsch-Französische Hochschule (DFH-UFA). Besides the main partner Université de Lorraine in Nancy, France, now also Coventry University, UK, and the Institute for Condensed Matter Physis of the National Academy of Sciences of Ukraine in Lviv, Ukraine, participate as associated partners. During the last week of September the TCO2014 conference \"Transparent Conductive Oxides – Fundamentals and Applications\" took place in honor of the 100th anniversary of the death of Prof. Dr. KarlW. Bädeker. In 1907 Karl Bädeker had discovered transparent conductive materials and oxides in Leipzig. About a hundred participants joined for many invited talks from international experts, intense discussion and new cooperations. At the end of November the by now traditional 15th nternational Workshop on Recent Developments in Computational Physics \"CompPhys14\" organized by Prof. Janke took place in Leipzig. Around 60 scientists from over 10 different countries exchanged ideas and discussed recent progress in several fields of computational physics. Work has successfully continued in the Centers of Excellence (Sonderforschungsbereiche) SFB 762 \"Functionality ofOxide Interfaces\" and SFB TRR 102 \"Polymers under Multiple Constraints: Restricted and Controlled Molecular Order and Mobility\" (just renewed for 2015-2019). Our activities and success are only possible with the generous support fromvarious funding agencies for which we are very grateful and which is individually acknowledged in the brief reports

    Electroceramics XIII:June, 24th-27th 2012, University of Twente, Enschede, The Netherlands

    Get PDF

    Report / Institute fĂĽr Physik

    Get PDF
    The 2016 Report of the Physics Institutes of the Universität Leipzig presents a hopefully interesting overview of our research activities in the past year. It is also testimony of our scientific interaction with colleagues and partners worldwide. We are grateful to our guests for enriching our academic year with their contributions in the colloquium and within our work groups

    Doctor of Philosophy

    Get PDF
    dissertationSpintronic devices are currently being researched as next-generation alternatives to traditional electronics. Electronics, which utilize the charge-carrying capabilities of electrons to store information, are fundamentally limited not only by size constraints, but also by limits on current flow and degradation, due to electro-migration. Spintronics devices are able to overcome these limitations, as their information storage is in the spin of electrons, rather than their charge. By using spin rather than charge, these current-limiting shortcomings can be easily overcome. However, for spintronic devices to be fully implemented into the current technology industry, their capabilities must be improved. Spintronic device operation relies on the movement and manipulation of spin-polarized electrons, in which there are three main processes that must be optimized in order to maximize device efficiencies. These spin-related processes are: the injection of spin-polarized electrons, the transport and manipulation of these carriers, and the detection of spin-polarized currents. In order to enhance the rate of spin-polarized injection, research has been focused on the use of alternative methods to enhance injection beyond that of a simple ferromagnetic metal/semiconductor injector interface. These alternatives include the use of oxide-based tunnel barriers and the modification of semiconductors and insulators for their use as ferromagnetic injector materials. The transport of spin-polarized carriers is heavily reliant on the optimization of materials' properties in order to enhance the carrier mobility and to quench spin-orbit coupling (SOC). However, a certain degree of SOC is necessary in order to allow for the electric-field, gate-controlled manipulation of spin currents. Spin detection can be performed via both optical and electrical techniques. Using electrical methods relies on the conversion between spin and charge currents via SOC and is often the preferred method for device-based applications. This dissertation presents experimental results on the use of oxides for fulfilling the three spintronic device requirements. In the case of spin injection, the study of dilute magnetic dielectrics (DMDs) shows the importance of doping on the magnetic properties of the resulting tunnel barriers. The study of spin transport in ZnO has shown that, even at room temperature, the spin diffusion length is relatively long, on the order of 100 nm. These studies have also probed the spin relaxation mechanics in ZnO and have shown that Dyakonov-Perel spin relaxation, operating according to Fermi-Dirac statistics, is the dominant spin relaxation mechanism in zinc oxide. Finally, spin detection in ZnO has shown that, similar to other semiconductors, by modifying the resistivity of the ZnO thin films, the spin Hall angle (SHA) can be enhanced to nearly that of metals. This is possible by enhancing extrinsic SOC due to skew-scattering from impurities as well as phonons. In addition, thermal spin injection has also been detected using ZnO, which results support the independently measured inverse spin-Hall effect studies. The work represented herein illustrates that oxide materials have the potential to enhance spintronic device potential in all processes pertinent to spintronic applications

    Report / Institute fĂĽr Physik

    Get PDF
    The 2016 Report of the Physics Institutes of the Universität Leipzig presents a hopefully interesting overview of our research activities in the past year. It is also testimony of our scientific interaction with colleagues and partners worldwide. We are grateful to our guests for enriching our academic year with their contributions in the colloquium and within our work groups

    Biomimetic route to hybrid nano-Composite scaffold for tissue engineering

    Get PDF
    Hydroxyapatite-poly(vinyl) alcohol-protein composites have been prepared by a biomimetic route at ambient conditions, aged for a fortnight at 30±2°C and given a shape in the form of blocks by thermal cycling. The structural characterizations reveal a good control over the morphology mainly the size and shape of the particles. Initial mechanical studies are very encouraging. Three biocompatibility tests, i.e., hemocompatibility, cell adhesion, and toxicity have been done from Shree Chitra Tirunal, Trivandrum and the results qualify their standards. Samples are being sent for more biocompatibility tests. Optimization of the blocks in terms of hydroxyapatite and polymer composition w.r.t the applications and its affect on the mechanical strength have been initiated. Rapid prototyping and a β-tricalcium – hydroxyapatite combination in composites are in the offing

    Report / Institute fĂĽr Physik

    Get PDF
    In this report the Institutes of Physics of the Universität Leipzig present their scientific activities and major achievements in the year 2003

    Ald processes development for hybrid nanodevices-like nanostructures

    Get PDF
    194 p.The development of new and innovative atomic structures displaying multifunctional properties goes together with progress in advanced processes which enable atomic level control. One leading deposition technique is Atomic layer deposition (ALD), which has emerged as a powerful tool for bond-specific functionalization and the growth of stoichiometric films over wafer scale and high area uniformity. ALD offers a wide range of functionalization routes by means of four processes such as vapor phase metalation (VPM), multiple pulsed vapor-phase infiltration (MPI), ALD and molecular layer deposition (MLD). As an example of VPM on soft molecules, Zn metalation on Enterobactin (H6EB) and FeEnterobactin (FeH3EB) were studied experimentally and theoretically. Thus, we showed that the VPM process could become a route to functionalize soft organic molecules with potential applications in the pharmaceutical field. Extending Zn metalation-VPM growth to hybrid nanostructures, in this case ML-(NH4)V7O16. nanostructured square and Mw-H2Ti3O7 nanotubes. Zn metalation-VPM process provides a way to functionalize soft nanostructured materials in order to change their crystal structure and thereby their magnetic and optical properties, without affect their morphology. The use of DEZn/H2O in MPI, promotes the nucleation of ZnO nanoparticles around the nanotube (cactus-like) affecting the morphology and surface properties. It was found that the electronic energy gap decreases with increasing Zn content, making the (ZnO)Ti3O7 nanoparticle/nanotube nanocomposites potentially useful as photoanode for dye-sensitized solar cells (DSCs) and sensors. The ALD growth of uniform MxOy thin films where M stands for V, Mn, Sn or Zn was undertaken. The preliminary results show successful deposition of Âż-MnO2, Âż-V2O5, SnxOy and ZnO stoichiometric films, uniform over large areas. This points towards the possible growth of these oxides which can be considered as energy materials. Finally, the growth of alucone thin films (AlO-T and AlO-A, T: terephthalate and A: adipate) by ALD and MLD was explored. Stoichiometric thin films with large area uniformity were obtained in both cases. The use of bifunctional monomers (aromatic and aliphatic carboxylate) in the growth of AlO-T and AlO-A thin films leads to a lamellar phase and to an amorphous one, respectively. The structure of AlO-T is obtained by optimizing four models and correlating experimental data with DFT calculations. The analysis of the electronic band gap using frontier orbital (HOMO-LUMO), alongside the uniform LiPF6 distribution through the AlO-T, point to future studies of AlO-T for anode and electrolyte nanomembranes with potential applications in carboxylates-based energy storage concepts. Thus, in this thesis we have shown the versatility of ALD processes to realize novel thin films and pursue various functionalization strategies

    Ald processes development for hybrid nanodevices-like nanostructures

    Get PDF
    194 p.The development of new and innovative atomic structures displaying multifunctional properties goes together with progress in advanced processes which enable atomic level control. One leading deposition technique is Atomic layer deposition (ALD), which has emerged as a powerful tool for bond-specific functionalization and the growth of stoichiometric films over wafer scale and high area uniformity. ALD offers a wide range of functionalization routes by means of four processes such as vapor phase metalation (VPM), multiple pulsed vapor-phase infiltration (MPI), ALD and molecular layer deposition (MLD). As an example of VPM on soft molecules, Zn metalation on Enterobactin (H6EB) and FeEnterobactin (FeH3EB) were studied experimentally and theoretically. Thus, we showed that the VPM process could become a route to functionalize soft organic molecules with potential applications in the pharmaceutical field. Extending Zn metalation-VPM growth to hybrid nanostructures, in this case ML-(NH4)V7O16. nanostructured square and Mw-H2Ti3O7 nanotubes. Zn metalation-VPM process provides a way to functionalize soft nanostructured materials in order to change their crystal structure and thereby their magnetic and optical properties, without affect their morphology. The use of DEZn/H2O in MPI, promotes the nucleation of ZnO nanoparticles around the nanotube (cactus-like) affecting the morphology and surface properties. It was found that the electronic energy gap decreases with increasing Zn content, making the (ZnO)Ti3O7 nanoparticle/nanotube nanocomposites potentially useful as photoanode for dye-sensitized solar cells (DSCs) and sensors. The ALD growth of uniform MxOy thin films where M stands for V, Mn, Sn or Zn was undertaken. The preliminary results show successful deposition of Âż-MnO2, Âż-V2O5, SnxOy and ZnO stoichiometric films, uniform over large areas. This points towards the possible growth of these oxides which can be considered as energy materials. Finally, the growth of alucone thin films (AlO-T and AlO-A, T: terephthalate and A: adipate) by ALD and MLD was explored. Stoichiometric thin films with large area uniformity were obtained in both cases. The use of bifunctional monomers (aromatic and aliphatic carboxylate) in the growth of AlO-T and AlO-A thin films leads to a lamellar phase and to an amorphous one, respectively. The structure of AlO-T is obtained by optimizing four models and correlating experimental data with DFT calculations. The analysis of the electronic band gap using frontier orbital (HOMO-LUMO), alongside the uniform LiPF6 distribution through the AlO-T, point to future studies of AlO-T for anode and electrolyte nanomembranes with potential applications in carboxylates-based energy storage concepts. Thus, in this thesis we have shown the versatility of ALD processes to realize novel thin films and pursue various functionalization strategies
    • …
    corecore