Synthesis, characterization and beyond

Sample Preparation, Environments and Synthesis

We use a wide variety of apparatuses to achieve high-pressure / high-temperature environments for both recoverable materials synthesis and in situ studies. We have a wide range of diamond anvil cells available, with varying degrees of optical access and temperature control options for different applications. We generally work at pressures <50 GPa and temperatures <2500 K, although higher pressures and temperatures are certainly possible.

For example, low temperatures are achieved within a cryostat and high temperatures are achieved using resistive or laser heating.

 

 

 

 

 

 

 

 

The 250 ton Paris-Edinburgh Press (VX3) is equipped with a Teledyne Isco syringe pump (30 ml capacity, 30,000 PSI) and Keysight power supply unit (9 V-220 A) and is used for recovering cubic millimeters of samples from high-pressure and high-temperature (HP-HT) synthesis experiments. The ‘conoidal’ anvils, pyrophyllite gaskets and cylindrical graphite heaters are currently used for high-temperature experiments. The typical pressure and temperatures routinely used are 6-7GPa and 1600K. This setup also has the capability to perform resistivity measurements under pressure using Keithley digital multi-meter. High-pressure experiments to 25 GPa are possible using a metallic gasket with sintered diamond anvils.

 

 

 

 

 

 

 

 

 

 

 

In collaboration with Yingwei Fei, we also perform materials synthesis experiments using the large-volume multianvil press lab, generating pressures up to 25 GPa and temperatures up to 2300 K. In collaboration with Reini Boehler, we are working to develop novel large-volume synthesis capabilities.

 

 

 

 

 

 

 

 

 

 

 

We maintain a variety of equipment for sample environment/preparation including a Cryoindustries DAC He cryostat, 300W IPG IR fiber laser, high-purity MBraun LABStar glovebox, Fritsch PUVERISETTE 7 premium planetary ball mill, quartz tube cutting and sealing station, Mellen tube furnaces, dying ovens etc.

 

The LABstar glovebox allows for experiments to be conducted and manipulated under an inert Ar atmosphere. The glove box is equipped with two antechambers, one small and one large, to allow for more efficient cycling. The box is equipped with a single column inert gas purification system that maintains O2 and H20 levels below 1 ppm. The interior of the box is equipped with a diamond anvil cell loading stage (camera, monitor, light sources), a balance accurate to 0.001 g, pellet press, and a vacuum sealing system. Available chemicals are maintained in an inventory list stored next to the glovebox.

 

The mellen microtherm furnace is an industrial box furnace setup for solid-state synthesis. The furnace can maintain temperatures up to 1800 °C and heats a volume of 6”x6”x6”. The oven is controlled by an Omega CN7800 controller and can run a variety of temperature profiles including slow heating and cooling. The Mellen split tube furnace operates at temperatures up to 1250ºC in air. The standard orientation of the furnace is horizontal, however, a vertical stand or a bench stand is available. The furnace has fast heat-up rates (30ºC per minute standard) and an integrated dual-display controller, making it easy to use. Tubes are easily attached to the turbo pump for dynamic pumping experiments. The Thermolyne small muffle furnace is the ideal choice for quick runs up to 1100ºC. The digital setpoint controller allows for a variety of custom heating profiles. The isotemp vacuum oven is an ideal setup for general vacuum drying and heating applications. The oven has a depth of 18” and a capacity of 1.5 cu. Ft. The oven can maintain temperatures up to 280 °C and can be monitored with the built-in LED controller. The controller can be set up for programs as long as seven days and can cycle on and off up to eight times per day.

 

 

 

 

 

 

 

 

 

The vacuum sealing line is used to isolate solid-state experiments under vacuum in glass tubing. The line is setup to receive various sizes of glass tubing, evacuate them, and seal the tubing with a hydrogen/oxygen torch. The system can maintain vacuum to at least 10-3 Torr during sealing.

 

 

The Fritsch pulverisette is suited for loss-free grinding to 100 nm of hard, medium-hard, and brittle materials. Grinding can be performed dry, in suspension, or in inert gas. The system maintains main disk rotational speeds of 100-1100 rpm and features a SelfLOCK sample chamber for absolutely safe operation. The system can run simultaneously on two samples with a capacity of 30 ml each.

 

 

 

 

 

 

 

 

 

 

 

Two Druck Pace5000 pressure controllers allow for precise application (or removal) of pressure for membrane DAC experiments.

 

Plenty of microscopes and all the tools needed for sample loading.

 

High-pressure gas loading facility.

 

Miniature ruby fluorescence system and scope with DSLR camera.

 

3D printer for rapid prototyping.

 

 

 

 

 

 

 

 

 

 

 

Sample Characterization

X-ray diffraction

We maintain three X-ray diffractometers for in-house structural studies

1) Bruker D8 Discover with Cu microfocus source. This multi-function X-ray diffractometer allows microanalysis with interchangeable collimators from 2mm-0.1mm. X,Y,Z translation is coupled with tilt and rotation for micro-positioning. Reflection, in-plane grazing incidence diffraction, small angle X-ray scattering, and transmission measurement geometries are accommodated. User can choose the 140 mm diameter Vantec500 area detector or high-resolution LynxeyeXE 1-D detector for the desired speed/resolution.

 

 

 

 

 

 

 

 

 

 

 

 

2) Bruker D2 Phaser (Cu) with Lynxeye 1-D detector for general powder diffraction. This powder X-ray diffractometer is quick and easy to use for obtaining high quality data in reflection geometry. An integrated flat screen allows real-time data monitoring.

 

 

 

 

 

 

 

 

 

 

 

3) Rigaku D/max with rotating anode (Mo) and scintillation detector for single crystal studies. The system is built around a robust Huber 4-circle goniometer.

 

 

 

 

 

 

 

 

 

 

 

Vibrational spectroscopy and optical characterization

We use a variety of spectroscopic methods and optical characterization. The high-resolution Raman spectrometer is built around a Princeton Instruments SP2750 spectrograph with PyLoN CCD. The SP2750 spectrograph has a focal length of 750 mm, aperture ratio of f/9.7, PMT resolution of 0.03 nm, CCD resolution of 0.06 nm and Linear dispersion of 1.03 nm/mm. PyLoN CCD camera is liquid nitrogen cooled down to -120°C. The green single frequency torus laser excitation wavelength is 532nm, with power of 150 mW. Three gratings of 300 g/mm, 1800 g/mm, and 2400 g/mm are available. LightField software is used to control the camera and spectrograph.

 

 

The Bruker Vertex with Hyperion microscope is used to collect Fourier transform spectra from the mid IR to the UV.

 

 

The Perkin-Elmer Lambda950 spectrophotometer is equipped with a 150mm InGaAs integrating sphere and PMT/InGaAs detector which work in the operating range 175-2500nm. The instrument is routinely used to measure absorbance, transmittance/reflectance of powders, pellets, recovered DAC gaskets and thin films. The integrating sphere expands the measurement capability of this instrument to include the total and diffuse reflectance of both specular and diffuse samples.

 

 

 

User facilities

We are regular users at the Advanced Photon Source and the Spallation Neutron Source.