K
Knut Urban
Researcher at Ernst Ruska Centre
Publications - 42
Citations - 2936
Knut Urban is an academic researcher from Ernst Ruska Centre. The author has contributed to research in topics: Transmission electron microscopy & Dislocation. The author has an hindex of 19, co-authored 42 publications receiving 2705 citations.
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Atomic-resolution imaging of oxygen in perovskite ceramics.
TL;DR: Using an imaging mode based on the adjustment of a negative value of the spherical-aberration coefficient of the objective lens of a transmission electron microscope, all types of atomic columns in the dielectric SrTiO3 and the superconductor YBa2Cu3O7 are imaged.
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Atomic-scale study of electric dipoles near charged and uncharged domain walls in ferroelectric films
TL;DR: Using the negative spherical-aberration imaging technique in an aberration-corrected transmission electron microscope, a large difference in atomic details between charged and uncharged domain walls is reported.
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Unit-cell scale mapping of ferroelectricity and tetragonality in epitaxial ultrathin ferroelectric films
Chun-Lin Jia,Valanoor Nagarajan,Jiaqing He,Lothar Houben,T. Zhao,Ramamoorthy Ramesh,Knut Urban,Rainer Waser +7 more
TL;DR: By means of high-resolution transmission electron microscopy, the degree of tetragonality and the displacements of cations away from the centrosymmetry positions in an ultrathin epitaxial PbTiO(3) film is mapped, finding that the maximum off-centre displacements for the central area of the film do not scale with the t Petragonality.
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A spherical-aberration-corrected 200 kV transmission electron microscope
TL;DR: In this paper, a hexapole corrector system was constructed for compensation of the spherical aberration of the objective lens of a transmission electron microscope, and an improvement of the point resolution from 0.24nm to better than 0.14nm was realized.
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Atomic-resolution measurement of oxygen concentration in oxide materials.
Chun-Lin Jia,Knut Urban +1 more
TL;DR: The modified Ti2O9 group unit thus formed reduces the grain boundary energy and provides a way of accommodating oxygen vacancies occurring in oxygen-deficient material by the formation of a nanotwin lamellae structure.