17 results
Search Results
Now showing 1 - 10 of 17
- ItemPhase transition and anomalous low temperature ferromagnetic phase in Pr 0.6Sr 0.4MnO 3 single crystals(New York, NY : Springer Science + Business Media B.V., 2009) Rößler, S.; Harikrishnan, S.; Naveen Kumar, C.M.; Bhat, H.L.; Elizabeth, S.; Rößler, U.K.; Steglich, F.; Wirth, S.We report on the magnetic and electrical properties of Pr 0.6Sr 0.4MnO 3 single crystals. This compound undergoes a continuous paramagnetic-ferromagnetic transition with a Curie temperature T C301 K and a first-order structural transition at T S64 K. At T S, the magnetic susceptibility exhibits an abrupt jump, and a corresponding small hump is seen in the resistivity. The critical behavior of the static magnetization and the temperature dependence of the resistivity are consistent with the behavior expected for a nearly isotropic ferromagnet with short-range exchange belonging to the Heisenberg universality class. The magnetization (M-H) curves below T S are anomalous in that the virgin curve lies outside the subsequent M-H loops. The hysteretic structural transition at T S as well as the irreversible magnetization processes below T S can be explained by phase separation between a high-temperature orthorhombic and a low-temperature monoclinic ferromagnetic phase.
- ItemMagnetic field effects of double-walled carbon nanotubes(São Carlos : Universidade Federal de São Carlos, 2006) Latgé, A.; Grimm, D.; Ferreira, M.S.A theoretical discussion of electronic and transport properties of a particular family of double-wall carbon nanotubes, named commensurate structures of the armchair type (n,n)@(2n,2n) is addressed. A single p-band tight binding hamiltonian is considered and the magnetic field is theoretically described by following the Peierls approximation into the hopping energies. Our emphasis is put on investigating the main effects of the geometrical aspects and relative positions of the tubes on the local density of states and on the conductance of the system. By considering intershell interactions between a set of neighboring atoms on the walls of the inner and outer tubes, we study the possibility of founding Aharonov-Bohm effects in the DWCNs when a magnetic field is applied along the axial direction.
- ItemElectronic structure and aspects of unconventional superconductivity in NaxCoO2.yH2O(São Carlos : Universidade Federal de São Carlos, 2003) Rosner, H.; Drechsler, S.-L.; Fuchs, G.; Handstein, A.; Wälte, A.; Müller, K.-H.We examine the electronic structure of NaxCoO2.yH2O within the local density approximation. The parametrization of the band which forms the largest hole-Fermi surface centered at G shows significant deviations from what is frequently assumed in recent sophisticated theoretical studies. In particular, the commonly used nearest neighbor approaches in the framework of single band pictures are found to be unrealistic. The special role of H2O in screening the disorder in the charge reservoir is briefly discussed and compared with the case of Y1–xCaxCu3O6+d.
- ItemNiederdimensionale thermoelektrische Materialien auf der Basis halbleitender Silizide und Silizium/Germanium-Übergittern : Abschlußbericht zum Verbundvorhaben Niederdimensionale thermoelektrische Materialien für Energiewandler(Hannover : Technische Informationsbibliothek (TIB), 2003) Heinrich, Armin; Schumann, J.[no abstract available]
- ItemSchlussbericht vom 05.07.2004 zum Thema: Verbundprojekt Picosekunden PEEM: Prozesse, Teilvorhaben: Schnelles magnetisches Schalten und Probenpräparation : bmb+f-Förderschwerpunkt Kondensierte Materie, Großgeräte der physikalischen Grundlagenforschung(Hannover : Technische Informationsbibliothek (TIB), 2004) Schneider, C.M.[no abstract available]
- ItemForscherverbund Magnetwerkstoffe - Teilvorhaben: Theorie der magneto-kristallinen Anisotropie von eisenreichen Übergangsmetall-Verbindungen : Schlußbericht(Dresden : Leibniz-Institut für Festkörper- und Werkstoffforschung, 2001) Richter, Manuel; Eschrig, Helmut[no abstract available]
- ItemMaßgeschneiderte Nano-Komponenten: Herstellung und Funktionalisierung (MANAKO) : Abschlussbericht : Berichtszeitraum: 01.07.2007 - 30.11.2008(Hannover : Technische Informationsbibliothek (TIB), 2009) Schmidt, Oliver G.; Mei, Y.F.; Huang, G.S.; Solovev, A.A.; Bermudez Urena, E.; Mönch, I.; Bolanos, V.; Ding, F.; Reindl, T.; Kiravittaya, S.[no abstract available]
- ItemIntrinsische Eigenschaften ferromagnetischer Phasen : Magnetwerkstoffe ; Abschlussbericht(Dresden : Leibniz-Institut für Festkörper- und Werkstoffforschung, 2000) Handstein, Axel; Müller, Karl-Hartmut[no abstract available]
- ItemLeichtbau mit thermoplastischen Nanocomposites (LB-Nanos), Teilprojekt: Synthese, Reinigung und Funktionalisierung von Multiwalled Carbon Nanotubes für die Verwendung in thermoplastischen Nanocomposites : Schlussbericht(Hannover : Technische Informationsbibliothek (TIB), 2009) Leonhardt, Albrecht; Ritschel, Manfred[no abstract available]
- ItemProjektskizze "Nanosonden in molekularen Kohlenstoffhüllen für biomedizinische Anwendungen" für Phase 2 des Förderprogramms "ForMaT" (Forschung für den Markt im Team) als Bestandteil der BMBF-Innovationsinitiative Neue Länder "Unternehmen Region" ; Vorhabenbezeichnung: ForMaT: Potentialscreening "Nanostrukturen in molekularen Kohlenstoffhülle"(Hannover : Technische Informationsbibliothek (TIB), 2009) Büchner, Bernd[no abstract available]