1 / 46

Mixed-valence vanadates at high-pressures Andrzej Grzechnik

Mixed-valence vanadates at high-pressures Andrzej Grzechnik Institute of Crystallography, RWTH Aachen University. Vanadium coordination polyhedra in vanadates in relation to the oxidation states of vanadium at atmospheric pressure.

zinna
Download Presentation

Mixed-valence vanadates at high-pressures Andrzej Grzechnik

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Mixed-valence vanadates at high-pressures AndrzejGrzechnik Institute of Crystallography, RWTH Aachen University

  2. Vanadium coordination polyhedra in vanadates in relation to the oxidation states of vanadium at atmospheric pressure P.Y. Zavalij and M.S. Whittingham, Acta Cryst. B55, 627 (1999)

  3. Vanadium coordination polyhedra in vanadates in relation to the oxidation states of vanadium at atmospheric pressure • ► Electrochemistry • ► Catalysis • ► Correlated electron systems • Spin-Peierls transitions • Spin gap formation • Charge, spin & orbitalordering Metal-insulatortransitions • ► Magnetism P.Y. Zavalij and M.S. Whittingham, Acta Cryst. B55, 627 (1999)

  4. Rutile type Binary vanadium oxides Wadsley phases: VnO2n+1 (n = 3, 4, 6) the VO2 – V2O5 system V2O5 (Pmmn) VO2 (P42/mnm)

  5. Rutile type Binary vanadium oxides Wadsley phases: VnO2n+1 (n = 3, 4, 6) the VO2 – V2O5 system V2O5 (Pmmn) VO2 (P42/mnm) n = 3 V3O7 (C2/c) An insulator and a uniaxial ferromagnet: H. Nishihara, Y. Ueda, K. Kosuge, H. Yasuoka, S. Kachi, J. Phys. Soc. Jpn. 47, 790 (1979).

  6. Rutile type Binary vanadium oxides Wadsley phases: VnO2n+1 (n = 3, 4, 6) the VO2 – V2O5 system V2O5 (Pmmn) VO2 (P42/mnm) n = 4 V4O9 (Pnma) An antiferromagnet: S. Yamazaki, C. Li, K. Ohoyama, M. Nishi, M. Ichihara, H. Ueda, Y. Ueda, J. Solid State Chem. 183, 1496 (2010).

  7. Rutile type Binary vanadium oxides Wadsley phases: VnO2n+1 (n = 3, 4, 6) the VO2 – V2O5 system V2O5 (Pmmn) VO2 (P42/mnm) n = 6 V6O13 (Pnma) A metal-insulator phase transition followed by an antiferromagnetic transition: Y. Ueda, K. Kosuge, S. Kachi, Mater. Res. Bull. 11, 293 (1976).

  8. Corundum type Rutile type Binary vanadium oxides Magnéli phases: VnO2n-1 (n = 3÷9) the V2O3 – VO2 system VO2 (P42/mnm) V2O3 (R-3c) V3O5 (Cc) V8O15 (P-1)

  9. Vanadium coordination polyhedra in vanadates in relation to the oxidation states of vanadium at high pressures?

  10. Vanadium coordination polyhedra in vanadates in relation to the oxidation states of vanadium at high pressures P An interplay of theeffects of a chemicalcomposition and of highpressureonthestructuralstability and physicalproperties of mixedvalencevanadates

  11. Ca3V2O8 at high pressures palmierite type R3c

  12. Ca3V2O8 at high pressures Onset of amorphization at about 10 GPa A. Grzechnik, Chem. Mater. 10, 1034 (1998) A. Grzechnik, J. Solid State Chem. 139, 161 (1998) palmierite type R3c

  13. Ca3V2O8 at high pressures HP-HT synthesis of a powder material 11 GPa, 1373 K C2/m palmierite type R3c A. Grzechnik, Solid State Sciences 4, 523 (2002)

  14. V2O5 and AxV2O5 (A = Li, Na, Cs, Ag, Mg, Ca, …; x ≤ 1) V2O5 (Pmmn) NaV2O5 (Pmmn)

  15. V2O5 and AxV2O5 (A = Li, Na, Cs, Ag, Mg, Ca, …; x ≤ 1) NaV2O5 (Pmmn) b-Na0.33V2O5 (C2/m) Wadsley-type bronze

  16. Pressure-induced superconductivity in b-Na0.33V2O5: TSC = 8 K, P = 8 GPa Phase transition from the charge ordered to the superconducting phase at 8 K and 8 GPa? T. Yamauchi, Y. Ueda, N. Môri, Phys. Rev. Lett. 89, 057002 (2002)

  17. Local structures in high-pressure phases of V2O5 A. Grzechnik, Chem. Mater. 10, 2507 (1998) I. Loa, A. Grzechnik, U. Schwarz, K. Syassen, M. Hanfland, R.K. Kremer, J. Alloys Comp. 317–318, 103 (2001)

  18. High-pressure phases of V2O5 and NaV2O5 from powder diffraction? A. Grzechnik, Chem. Mater. 10, 2507 (1998) I. Loa, A. Grzechnik, U. Schwarz, K. Syassen, M. Hanfland, R.K. Kremer, J. Alloys Comp. 317–318, 103 (2001)

  19. High-pressure phases of b-Na0.33V2O5 from powder diffraction? High-pressure synchrotron powder diffraction at room temperature K. Rabia, A. Pashkin, S. Frank, G. Obermeier, S. Horn, M. Hanfland, C.A. Kuntscher, High Press. Res. 29, 504 (2009)

  20. (NH4)2V3O8fresnoite Synchrotron single-crystaldiffraction (D3/Hasylab) A. Grzechnik, T.Z. Ren, J.M. Posse, K. Friese, Dalton Trans. 40, 4572 (2011) Ambient pressure 6.90 GPa V4+ V5+ P4bm

  21. (NH4)2V3O8fresnoite Synchrotron single-crystaldiffraction (D3/Hasylab) A. Grzechnik, T.Z. Ren, J.M. Posse, K. Friese, Dalton Trans. 40, 4572 (2011) Ambient Ambient pressure 6.90 GPa V4+ V5+ No charge transfer P4bm P4/mbm

  22. MV6O11 compounds (M = Na, K, Sr, Ba, Pb) P63/mmc M+V33+V34+O11 or M2+V43+V24+O11 NaV6O11: A. Grzechnik, Y. Kanke, K. Friese, J. Phys.: Condens. Matter 20, 285208 (2008) BaV6O11: K. Friese, Y. Kanke, A. Grzechnik, Acta Cryst. B65, 326 (2009) V(1)O6 M V(2)O6 V(1)O6 V(3)O5 regular Kagomé lattice Structures related to magnetoplumbite Pb(Fe3+,Mn3+)12O19

  23. Phasetransitions in NaV6O11: low T 64.2 K 80 K TH = 243 K  ║ Na+ Spontaneous magnetization with the easy axis II to [001] V4+(2)O6 V3+(1)O6 V4+(3)O5 ► A Curie-Weiss paramagnetic metal at ambient conditions ►Spontaneous magnetization is suppressed at high pressures (Tc ↓ P↑) while the TH temperature increases on compression (*) and is expected to be at 1.15 GPa and room T (*) T. Naka, T. Matsumoto, Y. Kanke, K. Murata, Physica B206/207, 853 (1995)

  24. Phasetransitions in BaV6O11: low T Single-crystal growth at 6 GPa and 1473-2323 K Yasushi Kanke (NIMS, Tsukuba) Ba2+ V(2)O6 V(1)O6 V(3)O5

  25. Phasetransitions in BaV6O11: low T Single-crystal growth at 6 GPa and 1473-2323 K Yasushi Kanke (NIMS, Tsukuba) P63mc ↔ P63/mmc 250 K Ba2+ 115 K 75 K V(2)O6 V(1)O6 V(3)O5 Specific heat

  26. Phasetransitions in BaV6O11: low T Single-crystal growth at 6 GPa and 1473-2323 K Yasushi Kanke (NIMS, Tsukuba) P63mc ↔ P63/mmc 250 K Ba2+ 115 K 75 K V(2)O6 No structural phase transitions (no Cmc21 phase) V(1)O6 V(3)O5 Specific heat

  27. Phasetransitions in BaV6O11: low T Single-crystal growth at 6 GPa and 1473-2323 K Yasushi Kanke (NIMS, Tsukuba) P63mc ↔ P63/mmc 250 K 115 K 115 K 75 K 75 K No structural phase transitions (no Cmc21 phase) Specific heat Magnetic susceptibility

  28. Phasetransitions in NaV6O11and BaV6O11: breakingtheKagomélattice

  29. Phasetransitions in NaV6O11and BaV6O11: breakingtheKagomélattice NaV6O11

  30. Phasetransitions in NaV6O11and BaV6O11: breakingtheKagomélattice V(1) V(2) 290 K 2.86 Å NaV6O11

  31. Phasetransitions in NaV6O11and BaV6O11: breakingtheKagomélattice V(1) V(2) 290 K 2.86 Å 85.5 K NaV6O11 2.72 Å 2.99 Å

  32. Phasetransitions in NaV6O11and BaV6O11: breakingtheKagomélattice V(1) V(2) 290 K 2.86 Å 85.5 K 4.2 GPa NaV6O11 2.72 Å 2.99 Å 3.01 Å 2.66 Å

  33. Phasetransitions in NaV6O11and BaV6O11: breakingtheKagomélattice NaV6O11 BaV6O11

  34. Phasetransitions in NaV6O11and BaV6O11: breakingtheKagomélattice NaV6O11 Hardly any bond valence changes at V sites BaV6O11 Bond valence changes at all V sites Charge transfer M V(2)O6 V(1)O6 V(3)O5

  35. Mixed-valencevanadates MV4O8 (M = Y, Yb, Lu) 3V3+ + 1V4+ K. Friese, Y. Kanke, A.N. Fitch, A. Grzechnik, Chem. Mater. 19, 4882 (2007) K. Friese, Y. Kanke, A.N. Fitch, W. Morgenroth, A. Grzechnik, Acta Cryst. B64, 652 (2008)

  36. →b Fe(1)O6 Fe(2)O6 Ca ↓a →b Pnam (Z = 4) a = 9.230 Å b = 10.705 Å c = 3.024 Å ↓c Orthorhombic Pnam a= 9.230 Å b=10.705 Å c= 3.024 Å Calcium ferrite type structure (CaFe2O4)

  37. →b V(1)O6 V(3)O6 V(2)O6 V(4)O6 Yb ↓a →b P 1 21/n 1 (Z = 4) a = 9.0648(3) Å b = 10.6215(4) Å c = 5.7607(1) Å  = 90.184(3)° ↓c a-YbV4O8

  38. →b V(1)O6 V(3)O6 V(2)O6 V(4)O6 Yb ↓a →b A 21/d 1 1 (Z = 8) a = 9.030(5) Å b = 21.44(3) Å c = 5.752(2) Å  = 89.911(3)° ↓c β-YbV4O8

  39. Polytypism, twinning, and compositecrystals in MV4O8 (M = Y, Yb, Lu) Average structure Pnam P121/n1 A21/d11 α-phase β-phase

  40. Phasetransitions in MV4O8 (M = Y, Yb, Lu) at lowtemperatures a-YV4O8 b-YV4O8 (a,b)-YV4O8 Q Magnetic susceptibility Specific heat Domain size effects: a ≈ 40-50 Å, b ≈ 500 Å

  41. Guinier simulation of synchrotron powder diffraction data for b-YbV4O8 A21/d11 (Z = 4) β-Phase A21/d11 (Z = 4) β’-Phase 180-185 K ID31/ESRF

  42. Isostructuralphasetransitions in a-YbV4O8 and b-YbV4O8 duetochargeordering at lowtemperatures (single-crystal data from ANKA & DESY) α-phase β-phase te Temperature [K] Temperature [K]

  43. High-pressurebehaviour of a-YbV4O8 and b-YbV4O8polytypes? P121/n1, Z =4 A21/d11, Z =8

  44. High-pressurebehaviour of a-YbV4O8 and b-YbV4O8polytypes? P121/n1, Z =4 A21/d11, Z =8 (DAC) SNBL/ESRF, PETRA III (DAC) SNBL/ESRF, PETRA III (0.3 mm capillary) ID31/ESRF (0.3 mm capillary) ID31/ESRF a-YbV4O8 seems to be stable at least to 16 GPa b-YbV4O8 seems to be stable at least to 10 GPa

  45. Thefuture: an interplay of theeffects of a chemicalcomposition and of highpressureonthestructuralstability and physicalproperties of mixedvalencevanadates ►In situ high-pressure x-raystudies (diamondanvilcells and multi-anvils) Phasetransitions P-T phasediagrams Chemicalreactions ►High-pressuresynthesis ►Physicalpropertiesunderhighpressures Magnetism Transportproperties

  46. Collaborators Karen Friese (JCNS, Jülich) Yasushi Kanke (NIMS, Tsukuba) Oleg Petracic (JCNS, Jülich) Georg Roth (RWTH Aachen University)

More Related