A CO₂ laser heating system for in situ high pressure-temperature experiments at HPCAT

Area of Science:

• High-pressure physics and materials science
• Synchrotron-based research
• Laser heating techniques

Background:

• Studying materials under extreme conditions (high pressure and temperature) is crucial for understanding their properties.
• Previous methods for laser heating in diamond anvil cells faced alignment challenges.
• Wide bandgap insulating materials require specialized heating techniques for high-pressure research.

Purpose of the Study:

• To develop and present a modular and portable CO2 laser heating system for synchrotron X-ray diffraction.
• To enable precise alignment of the heating laser and X-ray probe.
• To investigate the high-pressure, high-temperature behavior of materials, specifically ZrO2.

Main Methods:

• Utilized a CO2 laser heating setup integrated with a diamond anvil cell at HPCAT.
• Employed a mid-infrared microscope for precise alignment of the CO2 laser spot.
• Combined laser heating with synchrotron X-ray diffraction and optical pyrometry.
• Designed components for portability and compatibility with beamlines.

Main Results:

• Demonstrated improved room-temperature X-ray diffraction data quality for ZrO2 after CO2 laser annealing at 5.5 GPa.
• Obtained in-situ diffraction data for ZrO2 up to 2800 K at 5.5 GPa.
• Did not observe the postulated fluorite structure of ZrO2 under the studied conditions.

Conclusions:

• The developed CO2 laser heating system is effective for high-pressure, high-temperature research using synchrotron X-ray diffraction.
• The system enhances diffraction data quality and allows in-situ measurements of materials under extreme conditions.
• The study provides new insights into the high-pressure phase diagram of ZrO2.