1,721,069 research outputs found
Role of interband scattering in neutron irradiated MgB2 thin films by scanning tunnelling spectroscopy measurements
No full textA series of MgB2 thin films systematically disordered by neutron irradiation have been studied by scanning
tunneling spectroscopy. The c-axis orientation of the films allowed a reliable determination of the local density
of states of the band. With increasing disorder, the conductance peak moves towards higher voltages and
becomes lower and broader, indicating a monotonic increase of the gap and of the broadening parameter.
These results are discussed in the framework of two-band superconductivity
Different manganite systems studied by x-ray absorption and emission techniques at the Mn absorption edge
No full text(LaMnO3)2n(SrMnO3)n superlattices studied by polarized x-ray absorption at Mn L and O K edges
No full textCharge and magnetic excitations in hole- and electron-doped infinite layer cuprate superconductors
No full textSynthesis and properties of highly metallic orbital-ordered A-site manganites
No full textIn perovskite oxide materials, because of
the insertion of multiple valence states ions (e.g., Mn
in manganites) at atomic A-site (i.e., at the center of
perovskite cubic cell), an enhancement of the ferromagnetic
metallic state together with a strong orbital
order of Mn-ions is established. Such a feature goes
beyond the conventional theoretical framework for
which the kinetic energy of the free charge carriers
prevents the occurrence of a long-range orbital order.
We do provide a complete physical characterization of
these so-called A-site manganites by comparing
transport and structural properties of La0.7Sr0.3MnO3
and LaMnO3 thin films with different excess Mn
content and different oxygen content. A viable route to
successfully grow such class of materials as a function
of temperature and oxygen environment is provided.
The observed multi-order phase coexistence opens
unexplored perspectives toward the synthesis of new
intrinsic multi-functional materials
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Direct measurements of sheet resistance R2 in cuprate systems: evidence of fermionic scenario in Metal-Insultor transition
No full textThe metal-insulator transition (MIT) has been studied in Ba0.9Nd0.1CuO2+x/CaCuO2 ultrathin cuprate structures. Such structures allow for the direct measurement of the 2D sheet resistance R□, eliminating ambiguity in the definition of the effective thickness of the conducting layer in high temperature superconductors. The MIT occurs at room temperature for experimental values of R□ close to the 25.8 kΩ universal quantum resistance. All data confirm the assumption that each CaCuO2 layer forms a 2D superconducting sheet within the superconducting block, which can be described as weak-coupled equivalent sheets in parallel
Robustness of topological states in Bi2Se3 thin film grown by Pulsed Laser Deposition on (001)-oriented SrTiO3 perovskite
No full textWe report on the reproducible surface topological electron states in Bi2Se3 topological insulator thin films when epitaxially grown by Pulsed Laser Deposition (PLD) on (0 0 1)-oriented SrTiO3 (STO) perovskite substrates. Bi2Se3 has been reproducibly grown with single (0 0 1)-orientation and low surface roughness as controlled by ex-situ X-ray diffraction and in situ scanning tunnel microscopy and low-energy electron diffraction. Finally, in situ synchrotron radiation angle-resolved photo-emission spectroscopy measurements show a single Dirac cone and Dirac point at EB∼0.38 eV located in the center of the Brillouin zone likewise found from exfoliated single-crystals. These results demonstrate that the topological surface electron properties of PLD-grown Bi2Se3 thin films grown on (0 0 1)-oriented STO substrates open new perspectives for applications of multi-layered materials based on oxide perovskites
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