Structure determination at high pressures: X-ray diffraction · - Reconstructive phase transitions. Single crystal diffraction ... Phase transitions. Hysteresis. Examples Summer Under

$Page 1: Structure determination at high pressures: X-ray diffraction · - Reconstructive phase transitions. Single crystal diffraction ... Phase transitions. Hysteresis. Examples Summer Under$
Summer Under Pressure School , Madrid, 29th September 2015

Structure determination at high pressures:

X-ray diffraction

Julio Pellicer Porres

MALTA Consolider Team

Dpto. de Física Aplicada – ICMUV , Univ. València, Spain

[email protected]

1

Outline


Outline:

- X ray diffraction at high pressures.

2

XRD at high pressures

- Special needs.

- EDXRD

- ADXRD

- Single crystal XRD

- Examples.

- Synchrotron radiation.



3

Special needs of XRD high pressure experiments

Which are the limitations imposed by high pressure to XRD?

1. Sample size.

ID27, ESRF

MSPD, ALBA

Special needs



4

2. Absorption from anvils and sample

environment.

Cu K

keV

Mn K

keV

Ti K

keV

XRD at high pressures and synchrotron radiation


Special needs



5

An intense, highly collimated, hard (20-50 keV)

x-ray beam is needed

3. Limited angular range Ej: XRD spectrum simulations.

CuAlO2 (R-3m, a=2.86Å,

c=16.96Å).

l=0.4135 Å, E=30 keV

46 reflections

l=0.7093 Å, E=17.5 keV (Mo K)

10 reflections

XRD at high pressures and synchrotron radiation


Special needs

Outline


Outline:


6

- Special needs.

- EDXRD

- ADXRD


- Examples.


Synchrotron radiation



7

Synchrotron

Bending magnet

Wiggler Undulator




8

-Main advantages:

- Brilliance

- Wide wavelength range, from the IR to

hard x-rays.

- Linear and circular polarization.

- Possibility of a time pulsed source.

Synchrotron Radiation




9

General Structure of SR Beamline

Examples:

- Material Science and Power Diffraction BL (ALBA)

- Pression Structure Imagerie par Contraste à Haute Énergie (Psiché, Soleil)

- ID27 High Pressure BL, ID09A - White Beam Beamline, High Pressure

Station (ESRF)




Two different experimental approaches

- Bragg’s law:

10

Fixed q, variable l(E) Energy dispersive XRD (EDXRD)

Fixedl (E), variable q Angle dispersive XRD (ADXRD)


Outline


Outline:


11

EDXRD

- Special needs.

- EDXRD

- ADXRD


- Examples.




0 10 20 30 40 50

Inte

nsi

da

d

Energía (keV)

2q

Incident white

beam

(Wiggler)

Diffraction parallelogram

Amplificator

Multicanal

analyzer

Energy dispersive x-ray diffraction (EDXRD)

Main disadvantage:

12

The quantitative analysis of diffracted

intensities is not easy.

Usually only cell parameters

are obtained!

E

hcd lqsin2

qsin)(

199.6)(

keVEÅd

hkl

hkl Fixed q:

EDXRD



13

EDXRD set-up in ID30 (now ID27), ESRF

2q1. Entrance slit

2. HP cell (PE)

3. Cell support

(translation and/or

rotation)

4. Diffraction slits

5. Ge detector (next to a

liquid N2 dewar)

EDXRD



14

ZnSexTe1-x alloys

J. Pellicer-Porres et al.,

PRB 65, 121091 (2002)

PRB 71, 035210 (2005)

EDXRD

Outline


Outline:


15

ADXRD

- Special needs.

- EDXRD

- ADXRD


- Examples.




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Angle dispersive x-ray diffraction (ADXRD)

2qWhite beam

(undulator or

wiggler)

Monochromatic beam

Monocromator

Digitalization

Sample

Integration

Colimador 2D detector

(image plate, CCD)

Inte

nsi

ty

2q

lq sin2dhkl

hkl Ådq

l

sin2)( 0

fijo 0ll

ADXRD



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Example: Stanford Synchrotron Radiation Laboratory (SSRL)

ADXRD



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Berlinite (AlPO4)

- Rietveld refinements at very high

pressures (Mbar).


Nature Materials 6, 698-702 (2007)

P=14 GPa

P=97 GPa

ADXRD

Outline


Outline:


19

Single crystal XRD

- Special needs.

- EDXRD

- ADXRD


- Examples.




The Laue condition is not so easy to fulfill !

- The single crystal analysis is complicated under HP:

- Absorption from the sample environment.

- Limited access to the reciprocal space.

- Reflections from the sample environment.

- Long experiments.

- No global image.

- Reconstructive phase transitions.

Single crystal diffraction

𝑘 − 𝑘′ = 𝐾

Single crystal XRD



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Advantages in single crystal XRD (1/3) - There is no reflection overlapping (in particular for d<1.5 Å)

- There are no grain contacts

- Equations of state can be determined with high precision.

GaS equation of state

- Layered compound.

- 70x10x10 μm3 sample

- l=0.37 Å

- Image plate

- ~40 reflections


Phys. Stat. Sol. (b) 244, 169-173 (2007)

Single crystal XRD



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- Systematic absences /spatial group.

- Access to reciprocal vectors (opposed to distances).

- Accurate determination of intensities and structural factors.

- Structural models.

Jahn-Teller distortions in CuWO4

- Boehler-Almax DAC.

- 90 x 70 x 20 μm3 sample

- l=0.45 Å

- NaI point detector.

1P cP /2J. Ruiz-Fuertes et al., Chem. Mater. 23,

4220–4226 (2011)

Advantages in single crystal XRD (2/3)

Single crystal XRD



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10 GPa

14 GPa

119 GPa

Loubeyre et al.,

Nature 383, 702 (1996)

Hydrogen equation of state

- Thanks to the EDXRD configuration the

contribution from the diamonds to the background

(Compton scattering) is minimized

- It is possible to study light elements (small atomic form factors).

Advantages in single crystal XRD (3/3)

Single crystal XRD

Outline


Outline:


24

Examples

- Examples.

- Equation of state.

- Synthesis.

- Phase transitions. Hysteresis.

Examples


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-Wigner&Huntington (1935):

Transformation from a molecular solid to a

monoatomic metal at 25 GPa .

- N. W. Ashcroft (1968):

Metallic hydrogen would be a high

temperature superconductor.

Enormous difficulties, from both the experimental and

theoretical points of view!

Equation of state

Hydrogen at high pressures

Examples


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10 GPa

14 GPa

119 GPa

Hydrogen equation of state

Equation of state

Examples


27 J. Pellicer-Porres et al., Phys. Stat. Sol. (b) 244, 169-173 (2007)

GaS equation of state

- Layered compound.

- 70x10x10 μm3 sample

- l=0.37 Å

- Image plate

- ~40 reflections

Equation of state

Outline


Outline:


28

Phase transitions. Hysteresis.

- Examples.


- Synthesis.


Examples


Nano ZnO

ZnO

F. Decremps et al., EPL 51, 268–274 (2000)

M. Flórez and J. M. Recio et al., in “Introduction to High

Pressure Science and Technology”

Hysteresis and potential barriers

J. Pellicer-Porres et al., APL 81, 4820-4822 (2002)

0

V

P

G

T


Examples


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Science 249, 647 (1990)

- Is there a crystal-amorphous phase transition?

AlPO4

-Quartz homeotype

- Berlinites: ABO4

Spirals of alternate tetrahedra

in berlinite structure

Science 255, 1559 (1992)

Overcoming potential barriers: berlinite

PRL 71, 3143 (1993).


Examples


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S.M. Sharma et al, PRB 62, 8824 (2000).

- Example: Cmcm phase in AlPO4

Laser heating

a (Å) b (Å) c (Å)

S. M. Sharma et al. 5.06 6.77 5.19

J. Pellicer-Porres et al. 5.0365 7.2908 5.7491

J. Pellicer-Porres et al., Nat. Mat. 6, 698-702 (2007)


Overcoming potential barriers:

berlinite

Examples


32 32

- Phase transitions in ZnTe0.2Se0.8:

11 GPa 10.5 GPa 10.4 GPa

10.3 GPa 10.2 GPa

- Upstroke: ZBNaCl

- Downstroke: NaCl Cin ZB

Hysteresis and potential barriers: path selection


Examples


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ZnSexTe1-x alloys

J. Pellicer-Porres et al., PRB 65, 121091 (2002)

PRB 71, 035210 (2005)

Semiconductores III-V y II-VI

V. Ozolins and A. Zunger, PRL 82, 767 (1999)

Outline


Outline:


34

Synthesis

- Examples.


- Synthesis.


Examples


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H. Tracy Hall

1953

First diamond synthesis

1954/12/16

F.P. Bundy et al.

Nature 176, 51 (1955)

Hall, Rev. Sci. Instrum. 31, 125 (1960)

Diamond synthesis

Synthesis

Examples


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Utsumi et al, J.Phys.: Condens.

Mat. 16, S1017(2004)

“In situ” studies

Example: Photon Factory, Ni

Synthesis

Examples


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http://www.kobelco.co.jp/english/machinery/

products/ip/product/press_01.html

Industrial diamond

synthesis

Kobelco: Kobe Steel Group

30000 ton press

“Belt”-type

Pmax=6 GPa

1 liter

Synthesis


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Additional information:

Do not forget x-ray absorption!

Thank you for

your attention!

CRC, in press

Documents

Structure determination at high pressures: X-ray diffraction · - Reconstructive phase transitions. Single crystal diffraction ... Phase transitions. Hysteresis. Examples Summer Under