Bogdan Dabrowski

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Using resonant x-ray spectroscopies combined with density functional calculations, we find an asymmetric biaxial strain-induced d-orbital response in ultrathin films of the correlated metal LaNiO3 which are not accessible in the bulk. The sign of the misfit strain governs the stability of an octahedral "breathing" distortion, which, in turn, produces an(More)
We report the observation of quantum oscillations in the underdoped cuprate superconductor YBa2Cu4O8 using a tunnel-diode oscillator technique in pulsed magnetic fields up to 85 T. There is a clear signal, periodic in inverse field, with frequency 660+/-15 T and possible evidence for the presence of two components of slightly different frequency. The(More)
Negative refraction, which reverses many fundamental aspects of classical optics, can be obtained in systems with negative magnetic permeability and negative dielectric permittivity. This Letter documents an experimental realization of negative refraction at millimeter waves, finite magnetic fields, and cryogenic temperatures utilizing a multilayer stack of(More)
Comprehensive temperature scans of the resistivity of a high-quality sample of PrNiO3 were made under different pressures up to 30 kbar; they have revealed that the insulator phase is suppressed completely at P approximately equal to 13 kbar, transforming to a non-Fermi-liquid phase in which the resistivity varies as Deltarho=rho(T)-rho(0) approximately(More)
(1) Synthesis and new materials Svilen Bobev Arnold M. Guloy Shiou-Jyh Hwu Abdou Lachgar Susan E. Latturner Raymond E. Schaak Dong-Kyun Seo Slavi C. Sevov Andreas Stein (2) Structureeproperty relationship Bogdan Dabrowski John E. Greedan Martha Greenblatt Clare P. Grey Allan J. Jacobson Douglas A. Keszler Jing Li Mas A. Subramanian Younan Xia (3) Modeling(More)
The normal state in the hole underdoped copper oxide superconductors has proven to be a source of mystery for decades. The measurement of a small Fermi surface by quantum oscillations on suppression of superconductivity by high applied magnetic fields, together with complementary spectroscopic measurements in the hole underdoped copper oxide(More)
In order to characterize the spin-spin exchange interactions responsible for the Type-E' antiferromagnetic order in inhomogeneous RNiO3 perovskites (R=Y or rare earth), the pressure dependence of the Néel temperature T(N) was systematically measured for samples with T(N)<T(IM) and T(N)=T(IM); T(IM) is an insulator-metal transition temperature. Analysis of(More)
Ca3Co4O9 has a unique structure that leads to exceptionally high thermoelectric transport. Here we report the achievement of a 27% increase in the room-temperature in-plane Seebeck coefficient of Ca3Co4O9 thin films. We combine aberration-corrected Z-contrast imaging, atomic-column resolved electron energy-loss spectroscopy, and density-functional(More)
Ceramics, which exhibit high proton conductivity at moderate temperatures, are studied as electrolyte membranes or electrode components of fuel cells, electrolysers or CO2 converters. In severe operating conditions (high gas pressure/high temperature), the chemical activity towards potentially reactive atmospheres (water, CO2, etc.) is enhanced. This can(More)
Chromium-substituted Hgl_xCrxBa2CuO4+ ~ compounds have been synthesized. Cr can be incorporated into the structure with a solubility limit around x -0.27. Cr substitutes at the Hg site and is tetrahedrally coordinated to four oxygen atoms. Two of these are apical oxygen atoms that have moved to new positions (02') and two are in the Hg/Cr plane (03) at a (x(More)