0000000000293736
AUTHOR
J. Baier
A different look at the spin state of Co$^{3+}$ ions in CoO$_{5}$ pyramidal coordination
Using soft-x-ray absorption spectroscopy at the Co-$L_{2,3}$ and O-$K$ edges, we demonstrate that the Co$^{3+}$ ions with the CoO$_{5}$ pyramidal coordination in the layered Sr$_2$CoO$_3$Cl compound are unambiguously in the high spin state. Our result questions the reliability of the spin state assignments made so far for the recently synthesized layered cobalt perovskites, and calls for a re-examination of the modeling for the complex and fascinating properties of these new materials.
Different Look at the Spin State ofCo3+Ions in aCoO5Pyramidal Coordination
Using soft-x-ray absorption spectroscopy at the Co ${L}_{2,3}$ and O $K$ edges, we demonstrate that the ${\mathrm{Co}}^{3+}$ ions with the ${\mathrm{CoO}}_{5}$ pyramidal coordination in the layered ${\mathrm{Sr}}_{2}{\mathrm{CoO}}_{3}\mathrm{Cl}$ compound are unambiguously in the high spin state. Our result questions the reliability of the spin state assignments made so far for the recently synthesized layered cobalt perovskites and calls for a reexamination of the modeling for the complex and fascinating properties of these new materials.
First results of the CAST-RADES haloscope search for axions at 34.67 $��$eV
We present results of the Relic Axion Dark-Matter Exploratory Setup (RADES), a detector which is part of the CERN Axion Solar Telescope (CAST), searching for axion dark matter in the 34.67$��$eV mass range. A radio frequency cavity consisting of 5 sub-cavities coupled by inductive irises took physics data inside the CAST dipole magnet for the first time using this filter-like haloscope geometry. An exclusion limit with a 95% credibility level on the axion-photon coupling constant of g$_{a��}\gtrsim 4\times10^{-13} \text{GeV}^{-1}$ over a mass range of 34.6738 $��$eV < $m_a$ < 34.6771 $��$eV is set. This constitutes a significant improvement over the current strongest limit set by CAST…