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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
P.Y. Zavalij and M.S. Whittingham, Acta Cryst. B55, 627 (1999)
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 & orbital ordering
Metal-insulator transitions
► Magnetism
P.Y. Zavalij and M.S. Whittingham, Acta Cryst. B55, 627 (1999)
Rutile type
Binary vanadium oxides
Wadsley phases: VnO2n+1 (n = 3, 4, 6)
VO2 (P42/mnm)
the VO2 – V2O5 system
V2O5 (Pmmn)
Rutile type
Binary vanadium oxides
Wadsley phases: VnO2n+1 (n = 3, 4, 6)
VO2 (P42/mnm)
the VO2 – V2O5 system
V2O5 (Pmmn)
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).
Rutile type
Binary vanadium oxides
Wadsley phases: VnO2n+1 (n = 3, 4, 6)
VO2 (P42/mnm)
the VO2 – V2O5 system
V2O5 (Pmmn)
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).
Rutile type
Binary vanadium oxides
Wadsley phases: VnO2n+1 (n = 3, 4, 6)
VO2 (P42/mnm)
the VO2 – V2O5 system
V2O5 (Pmmn)
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).
Corundum type
Rutile type
Binary vanadium oxides
Magnéli phases: VnO2n-1 (n = 3÷9)
V2O3 (R-3c)
the V2O3 – VO2 system
VO2 (P42/mnm)
V3O5 (Cc)
V8O15 (P-1)
Vanadium coordination polyhedra in vanadates in relation to the oxidation states
of vanadium at high pressures?
Vanadium coordination polyhedra in vanadates in relation to the oxidation states
of vanadium at high pressures
P
An interplay of the effects of a chemical composition
and of high pressure on the structural stability
and physical properties of mixed valence vanadates
Ca3V2O8 at high pressures
palmierite type
R3c
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
Ca3V2O8 at high pressures
HP-HT synthesis of a powder material
11 GPa, 1373 K
C2/m
A. Grzechnik, Solid State Sciences 4, 523 (2002)
palmierite type
R3c
V2O5 and AxV2O5 (A = Li, Na, Cs, Ag, Mg, Ca, …; x ≤ 1)
V2O5 (Pmmn)
NaV2O5 (Pmmn)
V2O5 and AxV2O5 (A = Li, Na, Cs, Ag, Mg, Ca, …; x ≤ 1)
NaV2O5 (Pmmn)
b-Na0.33V2O5 (C2/m)
Wadsley-type bronze
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)
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)
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)
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)
(NH4)2V3O8 fresnoite
Ambient pressure
V4+
V5+
P4bm
Synchrotron single-crystal diffraction (D3/Hasylab)
A. Grzechnik, T.Z. Ren, J.M. Posse, K. Friese, Dalton Trans. 40, 4572 (2011)
6.90 GPa
(NH4)2V3O8 fresnoite
Ambient pressure
Synchrotron single-crystal diffraction (D3/Hasylab)
A. Grzechnik, T.Z. Ren, J.M. Posse, K. Friese, Dalton Trans. 40, 4572 (2011)
Ambient
6.90 GPa
V4+
V5+
P4bm
No charge transfer
P4/mbm
MV6O11 compounds
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)
(M = Na, K, Sr, Ba, Pb)
P63/mmc
M+V33+V34+O11 or M2+V43+V24+O11
V(1)O6
M
V(2)O6
V(1)O6
regular Kagomé lattice
V(3)O5
Structures related to magnetoplumbite Pb(Fe3+,Mn3+)12O19
64.2 K 80 K
TH = 243 K
Phase transitions in NaV6O11: low T

║
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 B 206/207, 853 (1995)
Single-crystal growth at 6 GPa and 1473-2323 K
Yasushi Kanke (NIMS, Tsukuba)
Phase transitions in BaV6O11: low T
Ba2+
V(2)O6
V(1)O6
V(3)O5
Single-crystal growth at 6 GPa and 1473-2323 K
Yasushi Kanke (NIMS, Tsukuba)
Phase transitions in BaV6O11: low T
P63mc ↔ P63/mmc
250 K
Ba2+
115 K
75 K
V(2)O6
V(1)O6
Specific heat
V(3)O5
Single-crystal growth at 6 GPa and 1473-2323 K
Yasushi Kanke (NIMS, Tsukuba)
Phase transitions in BaV6O11: low T
P63mc ↔ P63/mmc
250 K
Ba2+
115 K
75 K
V(2)O6
No structural phase transitions
(no Cmc21 phase)
Specific heat
V(1)O6
V(3)O5
Single-crystal growth at 6 GPa and 1473-2323 K
Yasushi Kanke (NIMS, Tsukuba)
Phase transitions in BaV6O11: low T
P63mc ↔ P63/mmc
250 K
115 K
115 K
75 K
75 K
No structural phase transitions
(no Cmc21 phase)
Specific heat
Magnetic susceptibility
Phase transitions in NaV6O11and BaV6O11: breaking the Kagomé lattice
Phase transitions in NaV6O11and BaV6O11: breaking the Kagomé lattice
5 .8 G P a
3 .0 5
3 .0 5
80 K
3 .0 0
8 5 .5 K
4 .2 G P a
3 .0 0
0 .4 9 G P a
2 .6 G P a
230 K
V (1 ) - V (1 ) d is ta n c e s [Å ]
2 .9 5
2 .9 5
1 .2 G P a
2 .9 0
2 .9 0
250 K
290K
2 .8 5
2 .8 5
2 .8 0
2 .8 0
2 .7 5
2 .7 5
2 .7 0
2 .7 0
2 .6 5
2 .6 5
NaV6O11
2 .6 0
360
362
364
366
368
370
3
U n it-c e ll vo lu m e [Å ]
372
374
376
378
380
382
384
3
U n it-c e ll vo lu m e [Å ]
386
2 .6 0
388
Phase transitions in NaV6O11and BaV6O11: breaking the Kagomé lattice
5 .8 G P a
3 .0 5
3 .0 5
80 K
3 .0 0
8 5 .5 K
4 .2 G P a
3 .0 0
0 .4 9 G P a
2 .6 G P a
V (1 ) - V (1 ) d is ta n c e s [Å ]
230 K
290 K
2 .9 5
2 .9 5
1 .2 G P a
2 .9 0
2 .9 0
250 K
290K
2 .8 5
2 .8 5
2 .8 0
2 .8 0
2.86 Å
2 .7 5
2 .7 5
2 .7 0
2 .7 0
2 .6 5
2 .6 5
NaV6O11
2 .6 0
360
362
364
366
368
370
3
U n it-c e ll vo lu m e [Å ]
372
374
376
378
380
382
384
3
U n it-c e ll vo lu m e [Å ]
386
2 .6 0
388
V(1)
V(2)
Phase transitions in NaV6O11and BaV6O11: breaking the Kagomé lattice
5 .8 G P a
3 .0 5
3 .0 5
80 K
3 .0 0
8 5 .5 K
4 .2 G P a
3 .0 0
0 .4 9 G P a
2 .6 G P a
V (1 ) - V (1 ) d is ta n c e s [Å ]
230 K
290 K
2 .9 5
2 .9 5
1 .2 G P a
2 .9 0
2 .9 0
250 K
290K
2 .8 5
2 .8 5
2 .8 0
2 .8 0
2.86 Å
2 .7 5
2 .7 5
85.5 K
2 .7 0
2 .7 0
2 .6 5
2 .6 5
NaV6O11
2 .6 0
360
362
364
366
368
370
3
U n it-c e ll vo lu m e [Å ]
372
374
376
378
380
382
384
3
2.72UÅn it-c e ll vo
2.99luÅm e [Å ]
386
2 .6 0
388
V(1)
V(2)
Phase transitions in NaV6O11and BaV6O11: breaking the Kagomé lattice
5 .8 G P a
3 .0 5
3 .0 5
80 K
3 .0 0
8 5 .5 K
4 .2 G P a
2 .6 G P a
230 K
290 K
2 .9 5
V (1 ) - V (1 ) d is ta n c e s [Å ]
V(1)
V(2)
3 .0 0
0 .4 9 G P a
2 .9 5
1 .2 G P a
2 .9 0
2 .9 0
250 K
290K
2 .8 5
2 .8 5
2 .8 0
2 .8 0
2.86 Å
2 .7 5
2 .7 5
85.5 K
2 .7 0
2 .7 0
2 .6 5
2 .6 5
4.2 GPa
NaV6O11
2 .6 0
360
362
364
366
368
370
3
U n it-c e ll vo lu m e [Å ]
372
374
376
378
380
382
384
3
386
2.72UÅn it-c e ll vo
2.99luÅm e [Å3.01
] Å
2 .6 0
388
2.66 Å
Phase transitions in NaV6O11and BaV6O11: breaking the Kagomé lattice
5 .8 G P a
3 .0 5
3 .0 5
80 K
3 .0 0
8 5 .5 K
4 .2 G P a
3 .0 0
0 .4 9 G P a
2 .6 G P a
230 K
V (1 ) - V (1 ) d is ta n c e s [Å ]
2 .9 5
2 .9 5
1 .2 G P a
2 .9 0
2 .9 0
250 K
290K
2 .8 5
2 .8 5
2 .8 0
2 .8 0
2 .7 5
2 .7 5
2 .7 0
2 .7 0
2 .6 5
2 .6 5
NaV6O11
2 .6 0
360
362
364
366
368
370
3
U n it-c e ll vo lu m e [Å ]
BaV6O11
372
374
376
378
380
382
384
3
U n it-c e ll vo lu m e [Å ]
386
2 .6 0
388
Phase transitions in NaV6O11and BaV6O11: breaking the Kagomé lattice
NaV6O11
Hardly any bond valence changes at V sites
M
BaV6O11
Bond valence changes at all V sites
Charge transfer
V(2)O6
V(1)O6
V(3)O5
Mixed-valence vanadates 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)
→b
Fe(1)O6
Fe(2)O6
Ca
↓a
→b
Pnam (Z = 4)
Orthorhombic
a = 9.230 Å
Pnam
b = 10.705 Å
9.230
ca=
= 3.024
Å Å
↓c
b=10.705 Å
c= 3.024 Å
Calcium ferrite type structure (CaFe2O4)
→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
b = 90.184(3)°
↓c
a-YbV4O8
→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
a = 89.911(3)°
↓c
β-YbV4O8
Polytypism, twinning, and composite crystals in MV4O8 (M = Y, Yb, Lu)
Average structure
Pnam
P121/n1
α-phase
A21/d11
β-phase
Phase transitions in MV4O8 (M = Y, Yb, Lu) at low temperatures
a-YV4O8
b-YV4O8
(a,b)-YV4O8
Magnetic susceptibility
Q
Specific heat
Domain size effects: a ≈ 40-50 Å, b ≈ 500 Å
Guinier simulation of synchrotron powder diffraction data for b-YbV4O8
A21/d11 (Z = 4)
β-Phase
180-185 K
A21/d11 (Z = 4)
β’-Phase
ID31/ESRF
Isostructural phase transitions in a-YbV4O8 and b-YbV4O8
due to charge ordering at low temperatures (single-crystal data from ANKA & DESY)
2,02
2,01
V1
V2
V3
V4
2,00
1,99
1,98
1,97
V1
V2
V3
V4
α-phase
1,96
1,95
0
50
100
150
200
250
average V-O distances in [Å]
average V-O distances in [Å]
2,02
2,01
2,00
V1
V2
V3
V4
1,99
1,98
β-phase
1,97
1,96
1,95
100
300
Temperature [K]
200
250
300
Temperature [K]
4,0
4,0
3,8
1003,6
150
200
250
V1
300
V2
3+
V3
V4
4+
V2
3,4
Temperatur
[K]
V1
3+
V2
V3
V4
4+
V2
3,2
3,0
2,8
3,8
bond valence sums [v.u.]
bond valence sums [v.u.]
150
V1
3+
V2
V3
V4
4+
V2
3,6
3,4
3,2
3,0
2,8
0
50
100
150
200
Temperature [K]
Temperature [K]
250
300
100
te
150
200
temperature [K]
250
Temperature [K]
300
High-pressure behaviour of a-YbV4O8 and b-YbV4O8 polytypes?
P121/n1, Z =4
A21/d11, Z =8
High-pressure behaviour of a-YbV4O8 and b-YbV4O8 polytypes?
Intensity (relative units)
P121/n1, Z =4
2
3
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
5
6
d-spacing (Å)
a-YbV4O8 seems to be stable
at least to 16 GPa
7
2
3
4
5
6
d-spacing (Å)
b-YbV4O8 seems to be stable
at least to 10 GPa
7
The future: an interplay of the effects of a chemical composition
and of high pressure on the structural stability and physical properties
of mixed valence vanadates
► In situ high-pressure x-ray studies (diamond anvil cells and multi-anvils)
Phase transitions
P-T phase diagrams
Chemical reactions
► High-pressure synthesis
► Physical properties under high pressures
Magnetism
Transport properties
Collaborators
Karen Friese (JCNS, Jülich)
Yasushi Kanke (NIMS, Tsukuba)
Oleg Petracic (JCNS, Jülich)
Georg Roth (RWTH Aachen University)

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