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@INPROCEEDINGS{Hakala:906822,
      author       = {Hakala, Branislav Viliam and Manousou, Dimitra K. and
                      Friese, Karen and Glazyrin, Konstantin and Crichton, Wilson
                      A. and Grzechnik, Andrzej},
      title        = {{H}igh-pressure crystal structures of {W}adsley-type
                      vanadium oxides {V}2{O}5 and {V}6{O}13},
      reportid     = {FZJ-2022-01716},
      year         = {2022},
      abstract     = {The so-called Wadsley phases with general formula VnO2n+1
                      form a homologous series ofcompounds [1,2]. They have arisen
                      much interest due to the observed metal-insulatortransitions
                      and their potential application as battery materials. The
                      crystal structures of theparent compound V2O5 and of V6O13
                      (n=3) at ambient conditions are closely related, being
                      builtup of edge and corner sharing building units, which can
                      be described as [VO5]-pyramids in V2O5(space group Pmmn) and
                      as [VO6]-octahedra in V6O13 (space group C2/m) [3,4].High
                      pressure Raman and powder diffraction investigations on V2O5
                      suggest a pressureinducedphase transition between 4 and 7
                      GPa [5,6]. A recent in-situ high-pressure powderdiffraction
                      study suggests an irreversible phase transition from α-V2O5
                      to an amorphous statearound 12.6 GPa while according to
                      other investigations V2O5 becomes only fully amorphousunder
                      20.2 GPa [7]. Under high-temperature high-pressure
                      conditions α-V2O5 converts into β-V2O5 (P21/m) [8].
                      Ex-situ high-pressure high-temperature synthesis in a multi
                      anvil pressyielded δ-V2O5 (C2/c) which is isostructural to
                      Sb2O59. Despite the high level of interest highpressure
                      investigations using single crystal diffraction have not
                      been performed, nor was theHP-HT phase diagram of V2O5
                      studied in situ up to know. In addition, despite the fact
                      that the lowtemperature metal-insulator transition in V6O13
                      has been very well studied [10,11], highpressure
                      investigations have not been performed so far on this
                      compound.We have now studied single crystals of V2O5 and
                      V6O13 as a function of pressure at PetraIII, Desy. The
                      studies on V2O5 show complete irreversible amorphization of
                      the sample above 7.3GPa and, moreover, anomalies are
                      observed between 3 and 4 GPa. To further investigate the
                      HPHTbehaviour of V2O5, we used the large volume press at
                      ID06 at the ESRF and followed theevolution of the sample
                      with in-situ synchrotron radiation. Heating of the amorphous
                      phase leadto the formation of the δ-V2O5 polymorph with
                      Sb2O5 structure, which can be recovered atambient
                      conditions. High pressure single crystal diffraction
                      experiments on V6O13 show ananomalous behaviour between 2
                      and 3 GPa, yet the ambient pressure polymorph seems to
                      bestable up to the highest pressures reached in the
                      experiment.},
      month         = {Mar},
      date          = {2022-03-14},
      organization  = {30th annual meeting of the German
                       Crystallographic Society (DGK), Ludwig
                       Maximilians Universität München +
                       online (Germany + online), 14 Mar 2022
                       - 17 Mar 2022},
      cin          = {JCNS-2 / PGI-4 / JARA-FIT},
      cid          = {I:(DE-Juel1)JCNS-2-20110106 / I:(DE-Juel1)PGI-4-20110106 /
                      $I:(DE-82)080009_20140620$},
      pnm          = {632 - Materials – Quantum, Complex and Functional
                      Materials (POF4-632) / 6G4 - Jülich Centre for Neutron
                      Research (JCNS) (FZJ) (POF4-6G4)},
      pid          = {G:(DE-HGF)POF4-632 / G:(DE-HGF)POF4-6G4},
      typ          = {PUB:(DE-HGF)1},
      url          = {https://juser.fz-juelich.de/record/906822},
}