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Papers by Emmanuel Soignard

Research paper thumbnail of High-pressure behavior of As_ {2} O_ {3}: Amorphous-amorphous and crystalline-amorphous transitions

Physical Review B, 2008

The room temperature compression of As 2 O 3 has been studied by in situ diamond anvil cell Raman... more The room temperature compression of As 2 O 3 has been studied by in situ diamond anvil cell Raman and x-ray diffraction up to a pressure of 35 GPa. Upon compression, we discovered a crystal-to-amorphous transition in arsenolite, while claudetite, which is another crystalline polymorph of As 2 O 3 , remains crystalline up to at least 40 GPa. We have also observed an amorphous-amorphous transition in As 2 O 3 glass at 25 GPa. This transition is characterized by a dramatic change in the Raman spectrum, which is reversible upon decompression. In situ diamond anvil cell x-ray diffraction of As 2 O 3 glass reveals that the amorphous-amorphous transition is associated with an increase in the arsenic coordination. The amorphous-amorphous transition is reversible with little hysteresis.

Research paper thumbnail of Pressure-induced crystallization of amorphous< equation>< font face='verdana'> Ge</font>< sub> 2</sub>< font face='verdana'> Sb</font>< sub> 2</sub>< font face='verdana'> Te</font>< sub> 5</sub></equation>

Structural transitions in amorphous red phosphorus were studied at ambient temperature and pressu... more Structural transitions in amorphous red phosphorus were studied at ambient temperature and pressures up to 12 GPa. Amorphous (red) phosphorus was observed to transform into crystalline black phosphorus at 7.5 ± 0.5 GPa using diamond anvil cell Raman spectroscopy, x-ray diffraction and a direct equation of state (EoS) measurement. The transition was found to be irreversible and the material recovered upon pressure cycling to 10 to 12 GPa was crystalline orthorhombic black phosphorus. A third order Birch-Murnaghan EoS was fit to the data and a bulk modulus (B0) of 11.2 GPa was measured for amorphous red phosphorus.

Research paper thumbnail of Thermal decomposition of ammonia borane at high pressures

The Journal of …, 2009

[The Journal of Chemical Physics 131, 104506 (2009)]. Johanna Nylén, Toyoto Sato, Emmanuel Soigna... more [The Journal of Chemical Physics 131, 104506 (2009)]. Johanna Nylén, Toyoto Sato, Emmanuel Soignard, Jeffery L. Yarger, Emil Stoyanov, Ulrich Häussermann. Abstract. ... High-pressure temperature-dependent Raman studies were performed in a Merrill–Bassett type DAC. ...

Research paper thumbnail of Bimodal phase percolation model for the structure of Ge-Se glasses and the existence of the intermediate phase

... Pierre Lucas,1 Ellyn A. King,1,2 Ozgur Gulbiten,1 Jeffery L. Yarger,3 Emmanuel Soignard,3 and... more ... Pierre Lucas,1 Ellyn A. King,1,2 Ozgur Gulbiten,1 Jeffery L. Yarger,3 Emmanuel Soignard,3 and Bruno Bureau2 1Department of ... resonance and Raman study of GexSe1−x glasses indicate that the glass structure is composed of intertwined microdomains of GeSe2 and Sen. ...

Research paper thumbnail of Pressure-induced transformations in crystalline and vitreous

Solid State …, 2009

Structural transitions in crystalline and vitreous PbGeO 3 were studied at pressures up to 20 GPa... more Structural transitions in crystalline and vitreous PbGeO 3 were studied at pressures up to 20 GPa. Crystalline PbGeO 3 was observed to undergo a pressure-induced amorphization between 12-18 GPa. Vitreous PbGeO 3 was found to exhibit an amorphous-to-amorphous transition in a similar pressure range. The structural and thermal properties of the pressure-cycled PbGeO 3 materials were further studied with high-energy x-ray diffraction and differential scanning calorimetry. The properties were then compared to those of thermally quenched glass and ball-milled PbGeO 3 samples. The structure of pressure-amorphized PbGeO 3 was found to closely resemble that of ball-milled PbGeO 3 . However, the thermal properties probed by differential scanning calorimetry exhibited significant differences to those of thermally quenched PbGeO 3 glass.

Research paper thumbnail of A perforated diamond anvil cell for high-energy x-ray diffraction of liquids and amorphous solids at high pressure

Review of Scientific Instruments, 2010

Diamond anvil cells ͑DACs͒ are widely used for the study of materials at high pressure. The typic... more Diamond anvil cells ͑DACs͒ are widely used for the study of materials at high pressure. The typical diamonds used are between 1 and 3 mm thick, while the sample contained within the opposing diamonds is often just a few microns in thickness. Hence, any absorbance or scattering from diamond can cause a significant background or interference when probing a sample in a DAC. By perforating the diamond to within 50-100 m of the sample, the amount of diamond and the resulting background or interference can be dramatically reduced. The DAC presented in this article is designed to study amorphous materials at high pressure using high-energy x-ray scattering ͑Ͼ60 keV͒ using laser-perforated diamonds. A small diameter perforation maintains structural integrity and has allowed us to reach pressures Ͼ50 GPa, while dramatically decreasing the intensity of the x-ray diffraction background ͑primarily Compton scattering͒ when compared to studies using solid diamonds. This cell design allows us for the first time measurement of x-ray scattering from light ͑low Z͒ amorphous materials. Here, we present data for two examples using the described DAC with one and two perforated diamond geometries for the high-pressure structural studies of SiO 2 glass and B 2 O 3 glass.

Research paper thumbnail of Reversible elastic deformation of functionalized sp2 carbon at pressures of up to 33 GPa

Applied Physics Letters, 2014

ABSTRACT

Research paper thumbnail of High-pressure behavior of As_ {2} O_ {3}: Amorphous-amorphous and crystalline-amorphous transitions

Physical Review B, 2008

The room temperature compression of As 2 O 3 has been studied by in situ diamond anvil cell Raman... more The room temperature compression of As 2 O 3 has been studied by in situ diamond anvil cell Raman and x-ray diffraction up to a pressure of 35 GPa. Upon compression, we discovered a crystal-to-amorphous transition in arsenolite, while claudetite, which is another crystalline polymorph of As 2 O 3 , remains crystalline up to at least 40 GPa. We have also observed an amorphous-amorphous transition in As 2 O 3 glass at 25 GPa. This transition is characterized by a dramatic change in the Raman spectrum, which is reversible upon decompression. In situ diamond anvil cell x-ray diffraction of As 2 O 3 glass reveals that the amorphous-amorphous transition is associated with an increase in the arsenic coordination. The amorphous-amorphous transition is reversible with little hysteresis.

Research paper thumbnail of Pressure-induced crystallization of amorphous< equation>< font face='verdana'> Ge</font>< sub> 2</sub>< font face='verdana'> Sb</font>< sub> 2</sub>< font face='verdana'> Te</font>< sub> 5</sub></equation>

Structural transitions in amorphous red phosphorus were studied at ambient temperature and pressu... more Structural transitions in amorphous red phosphorus were studied at ambient temperature and pressures up to 12 GPa. Amorphous (red) phosphorus was observed to transform into crystalline black phosphorus at 7.5 ± 0.5 GPa using diamond anvil cell Raman spectroscopy, x-ray diffraction and a direct equation of state (EoS) measurement. The transition was found to be irreversible and the material recovered upon pressure cycling to 10 to 12 GPa was crystalline orthorhombic black phosphorus. A third order Birch-Murnaghan EoS was fit to the data and a bulk modulus (B0) of 11.2 GPa was measured for amorphous red phosphorus.

Research paper thumbnail of Thermal decomposition of ammonia borane at high pressures

The Journal of …, 2009

[The Journal of Chemical Physics 131, 104506 (2009)]. Johanna Nylén, Toyoto Sato, Emmanuel Soigna... more [The Journal of Chemical Physics 131, 104506 (2009)]. Johanna Nylén, Toyoto Sato, Emmanuel Soignard, Jeffery L. Yarger, Emil Stoyanov, Ulrich Häussermann. Abstract. ... High-pressure temperature-dependent Raman studies were performed in a Merrill–Bassett type DAC. ...

Research paper thumbnail of Bimodal phase percolation model for the structure of Ge-Se glasses and the existence of the intermediate phase

... Pierre Lucas,1 Ellyn A. King,1,2 Ozgur Gulbiten,1 Jeffery L. Yarger,3 Emmanuel Soignard,3 and... more ... Pierre Lucas,1 Ellyn A. King,1,2 Ozgur Gulbiten,1 Jeffery L. Yarger,3 Emmanuel Soignard,3 and Bruno Bureau2 1Department of ... resonance and Raman study of GexSe1−x glasses indicate that the glass structure is composed of intertwined microdomains of GeSe2 and Sen. ...

Research paper thumbnail of Pressure-induced transformations in crystalline and vitreous

Solid State …, 2009

Structural transitions in crystalline and vitreous PbGeO 3 were studied at pressures up to 20 GPa... more Structural transitions in crystalline and vitreous PbGeO 3 were studied at pressures up to 20 GPa. Crystalline PbGeO 3 was observed to undergo a pressure-induced amorphization between 12-18 GPa. Vitreous PbGeO 3 was found to exhibit an amorphous-to-amorphous transition in a similar pressure range. The structural and thermal properties of the pressure-cycled PbGeO 3 materials were further studied with high-energy x-ray diffraction and differential scanning calorimetry. The properties were then compared to those of thermally quenched glass and ball-milled PbGeO 3 samples. The structure of pressure-amorphized PbGeO 3 was found to closely resemble that of ball-milled PbGeO 3 . However, the thermal properties probed by differential scanning calorimetry exhibited significant differences to those of thermally quenched PbGeO 3 glass.

Research paper thumbnail of A perforated diamond anvil cell for high-energy x-ray diffraction of liquids and amorphous solids at high pressure

Review of Scientific Instruments, 2010

Diamond anvil cells ͑DACs͒ are widely used for the study of materials at high pressure. The typic... more Diamond anvil cells ͑DACs͒ are widely used for the study of materials at high pressure. The typical diamonds used are between 1 and 3 mm thick, while the sample contained within the opposing diamonds is often just a few microns in thickness. Hence, any absorbance or scattering from diamond can cause a significant background or interference when probing a sample in a DAC. By perforating the diamond to within 50-100 m of the sample, the amount of diamond and the resulting background or interference can be dramatically reduced. The DAC presented in this article is designed to study amorphous materials at high pressure using high-energy x-ray scattering ͑Ͼ60 keV͒ using laser-perforated diamonds. A small diameter perforation maintains structural integrity and has allowed us to reach pressures Ͼ50 GPa, while dramatically decreasing the intensity of the x-ray diffraction background ͑primarily Compton scattering͒ when compared to studies using solid diamonds. This cell design allows us for the first time measurement of x-ray scattering from light ͑low Z͒ amorphous materials. Here, we present data for two examples using the described DAC with one and two perforated diamond geometries for the high-pressure structural studies of SiO 2 glass and B 2 O 3 glass.

Research paper thumbnail of Reversible elastic deformation of functionalized sp2 carbon at pressures of up to 33 GPa

Applied Physics Letters, 2014

ABSTRACT