crystal growth under high pressure - ames laboratorycanfield.physics.iastate.edu/course/crystal...

Crystal Growth under High Pressure

Valentin Taufour


• In previous lectures: – Pressure units, pressure mediums – Measurements in high pressure cells

• Interest of high pressure for crystal growth

– – –

• How does our high pressure furnace work ? – Cubic high pressure set up – A few tricks to get a sense of high pressure experiments

pressure can modify the stability of some crystal structures which remain stable at ambient pressure due to the transformation barriers

Interest of high pressure for crystal growth

What does it mean ?

pressure can modify the stability of some crystal structures which remain stable at ambient pressure due to the transformation barriers


Examples of metastable materials ?

Metastable state

pressure can modify the stability of some crystal structures which remain stable at ambient pressure due to the transformation barriers Famous example of Diamond

Metastable state


pressure can modify the stability of some crystal structures which remain stable at ambient pressure due to the transformation barriers Steel is also metastable

Martensite is formed in carbon steels by the rapid cooling (quenching) of austenite at such a high rate that carbon atoms do not have time to diffuse out of the crystal structure in large enough quantities to form cementite (Fe3C)


Examples of materials grown under high pressure in the last 6 months

Interest of high pressure for crystal growth pressure can modify the stability of some crystal structures which remain stable at ambient pressure due to the transformation barriers

Diamond Li-Si phases c-BN BCN

In2NiMnO6

Sr2Can-1CunOy

CxSr2Ca2Cu3Oz

ThB4O8

UB4O8

BaIrO3

BaOsO3

Fe8B15O28(OH)8 ScRhO3

InRhO3 U2[BO4][PO4] Sr1-yBayRuO3

Bi4O4S3 Mo3S4

Sr3V5S11

FeS2

K2PtH6

Rb2PtH6

Cs2PtH6

Mg3CuHx

IrH3

Li2Ca3[N2]3

S in alpha-HfNBr IrNx

SrCu3Fe4O12

CaCu3V4O12

CaMn3V4O12

LaB2O4F CeB2O4F Mn2FeNbO6

Mn2FeTaO6

NaCr2O4

Sr3Co2O6

BiCu3Mn4-xFexO12

CdRh2O4

[Sr2O2]qCoO2

AgInxSb1-xTe2

B Mg2C Ce7Au13+xGe10-x

Ag3.4In3.7Sb76.4Te16.5

materials leading to publications between July 2013 and December 2013 with “high pressure synthesis” Source: Web Of Science


• In previous lectures: – Pressure units, pressure mediums

– Measurements in high pressure cells

• Interest of high pressure for crystal growth – pressure can modify the stability of some crystal structures which

remain stable at ambient pressure due to the transformation barriers

– pressure can increase the solid solubility

• How does our high pressure furnace work ? – Cubic high pressure set up

– A few tricks to get a sense of high pressure experiments

1000

800

600

400

200

0

T (

ºC)

20151050

at. % SiAl

0 GPa

1.6

577 ºC

660 ºC

11.3

pressure can increase the solid solubility

H. Mii et al. Japanese Journal of Applied Physics 15 777 (1976)


How much Si can you substitute into Al ? How ?

1000

800

600

400

200

0

T (

ºC)

20151050

at. % SiAl

0 GPa 2.8 GPa

1.6

577 ºC

660 ºC

11.3

10

660 ºC

840 ºC







Why is it interesting for us ?

1000

800

600

400

200

0

T (

ºC)

20151050

at. % SiAl

0 GPa 2.8 GPa 5.4 GPa

1.6

577 ºC

660 ºC

11.3

10

660 ºC

840 ºC

970 ºC


V. V. Brazhkin et al. J. Phys.: Condens. Matter 5 5933 (1993)

See also N. E. Sluchanko et al. Phys. Rev. B 51 1122 (1995)



1000

800

600

400

200

0

T (

ºC)

20151050

at. % SiAl

0 GPa 2.8 GPa 5.4 GPa

1.6

577 ºC

660 ºC

11.3

10

660 ºC

840 ºC

970 ºC


Ca1-xPrxFe2As2

Try to get higher Pr content into Ca1-xPrxFe2As2



Pr 25%

Pr 30%

Ca1-xPrxFe2As2

Try to get higher Pr content into Ca1-xPrxFe2As2


Unfortunately, did not induce superconductivity




– pressure can modify the stability of some crystal structures which remain stable at ambient pressure due to the transformation barriers

– pressure can increase the solid solubility – pressure can increase the liquidus temperature and the boiling

temperature

• How does our high pressure furnace work ?

– Cubic high pressure set up – A few tricks to get a sense of high pressure experiments

pressure can increase the liquidus temperature and the boiling temperature


What are the 3 regions on the phase diagram ?



water/ triethylene glycol (TEG) B. Bender et al. Braz. J. Chem. Eng. 30 75 (2013)



G. Balducci et al. J. Phys. Chem. Solids 66 292 (2005)

water/ triethylene glycol (TEG) B. Bender et al. Braz. J. Chem. Eng. 30 75 (2013)



G. Balducci et al. J. Phys. Chem. Solids 66 292 (2005) V. Z. Turkevich et al. High Pressure Res. 29 87 (2009)

How would you grow MgB2 ?



V. Z. Turkevich et al. High Pressure Res. 29 87 (2009)

10

8

6

4

2

0

(

m)

403020100

T (K)

MgB2 single crystal





– pressure can increase the solid solubility – pressure can increase the liquidus temperature and the boiling

temperature



Our high pressure furnace, where is it?

Our high pressure furnace: the Beast

max pressure : 3.3 GPa max temperature : 1800 C

Our high pressure furnace: cubic anvils


Our high pressure furnace: cubic anvils

The press and the anvils give us the high pressure, but what do I need to make a furnace?

Pyrophyllite: Al2Si4O10(OH)2


Our high pressure furnace: crucible


Our high pressure furnace: crucible


Our high pressure furnace

Although pyrophyllite is very hard, it flows like a soft chewing gum at 3 GPa.







– pressure can increase the solid solubility – pressure can increase the liquidus temperature and the boiling temperature



• get 3.3 GPa without breaking anything • measure the temperature at 3.3 GPa • get 1700 C in the furnace, not on the anvils

Get 3.3 GPa, without breaking anything Compressive strength of tungsten carbide: 4-5.93 GPa Transverse rupture strength: 1.60-2.85 GPa Carbide is classified technically as a “brittle” material since it exhibits little or no plastic deformation preceding the initiation of a crack and total failure.

Our high pressure furnace: a few tricks

Get 3.3 GPa, without breaking anything

Avoid stick-slip motion of the anvils Use molybdenite powder as a solid lubricant

Compressive strength of tungsten carbide: 4-5.93 GPa Transverse rupture strength: 1.60-2.85 GPa Carbide is classified technically as a “brittle” material since it exhibits little or no plastic deformation preceding the initiation of a crack and total failure.


Avoid stick-slip motion of the anvils Use molybdenite powder as a solid lubricant Use mylar sheets on the side with PTFE lubricant Keep anvils level

Get 3.3 GPa, without breaking anything Our high pressure furnace: a few tricks

Get the thermocouple at 3.3 GPa Our high pressure furnace: a few tricks

Get the thermocouple into a pyrophyllite cube squeezed to 3.3 GPa from every sides. How would you do that?

Get the thermocouple at 3.3 GPa

Alumina tubing as an insulator near the heater Make a strong thermocouple connection make a bent of the wire to allow deformation


Use G10 spacers

Get the thermocouple at 3.3 GPa Our high pressure furnace: a few tricks

Get the pyrophyllite at 3.3 GPa at 1700 C

Pre heat the pyrophyllite slowly to avoid exothermic dehydratation


batch to batch variation

Thank you for your attention

crystal growth under high pressure - ames laboratorycanfield.physics.iastate.edu/course/crystal...

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