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@ARTICLE{Kaa:480798,
      author       = {Kaa, Johannes M. and Sternemann, Christian and Appel, Karen
                      and Cerantola, Valerio and Preston, Thomas and Albers,
                      Christian and Elbers, Mirko and Libon, Lélia and Makita,
                      Mikako and Pelka, Alexander and Petitgirard, Sylvain and
                      Plückthun, Christian and Roddatis, Vladimir and Sahle,
                      Christoph J. and Spiekermann, Georg and Schmidt, Christian
                      and Schreiber, Anja and Sakrowski, Robin and Tolan, Metin
                      and Wilke, Max and Zastrau, Ulf and Konôpková, Zuzana},
      title        = {{S}tructural and electron spin state changes in an x-ray
                      heated iron carbonate system at the {E}arth's lower mantle
                      pressures},
      journal      = {Physical review research},
      volume       = {4},
      number       = {3},
      issn         = {2643-1564},
      address      = {College Park, MD},
      publisher    = {APS},
      reportid     = {PUBDB-2022-03971},
      pages        = {033042},
      year         = {2022},
      abstract     = {The determination of the spin state of iron-bearing
                      compounds at high pressure and temperature is crucial for
                      our understanding of chemical and physical properties of the
                      deep Earth. Studies on the relationship between the
                      coordination of iron and its electronic spin structure in
                      iron-bearing oxides, silicates, carbonates, iron alloys, and
                      other minerals found in the Earth's mantle and core are
                      scarce because of the technical challenges to simultaneously
                      probe the sample at high pressures and temperatures. We used
                      the unique properties of a pulsed and highly brilliant x-ray
                      free electron laser (XFEL) beam at the High Energy Density
                      (HED) instrument of the European XFEL to x-ray heat and
                      probe samples contained in a diamond anvil cell. We heated
                      and probed with the same x-ray pulse train and
                      simultaneously measured x-ray emission and x-ray diffraction
                      of an FeCO$_3$ sample at a pressure of 51 GPa with up to
                      melting temperatures. We collected spin state sensitive Fe
                      Kβ$_{1,3}$ fluorescence spectra and detected the sample's
                      structural changes via diffraction, observing the inverse
                      volume collapse across the spin transition. During x-ray
                      heating, the carbonate transforms into orthorhombic
                      Fe$_4$C$_3$O$_{12}$ and iron oxides. Incipient melting was
                      also observed. This approach to collect information about
                      the electronic state and structural changes from samples
                      contained in a diamond anvil cell at melting temperatures
                      and above will considerably improve our understanding of the
                      structure and dynamics of planetary and exoplanetary
                      interiors.},
      cin          = {DOOR ; HAS-User / $XFEL_E1_HED$},
      ddc          = {530},
      cid          = {I:(DE-H253)HAS-User-20120731 /
                      $I:(DE-H253)XFEL_E1_HED-20210408$},
      pnm          = {6G3 - PETRA III (DESY) (POF4-6G3)},
      pid          = {G:(DE-HGF)POF4-6G3},
      experiment   = {EXP:(DE-H253)XFEL-HED-20150101 /
                      EXP:(DE-H253)P-P02.2-20150101 / EXP:(DE-H253)P-P01-20150101},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000829259500003},
      doi          = {10.1103/PhysRevResearch.4.033042},
      url          = {https://bib-pubdb1.desy.de/record/480798},
}