Diamond anvil cell with boron-doped diamond heater for high-pressure synthesis and in situ transport measurements

At a Glance

Metadata	Details
Publication Date	2021-08-02
Journal	Applied Physics Letters
Authors	Ryo Matsumoto, Sayaka Yamamoto, Shintaro Adachi, Takeshi Sakai, Tetsuo Irifune
Institutions	Ehime University, National Institute for Materials Science
Citations	10
Analysis	Full AI Review Included

Executive Summary

This study details the development and application of a novel Diamond Anvil Cell (DAC) platform featuring integrated, reusable boron-doped diamond (BDD) components for simultaneous high-pressure synthesis and in-situ electrical transport measurements.

Integrated Functionality: The DAC incorporates BDD films fabricated directly onto the diamond anvil surface, serving as transport measurement probes, a resistive heater, and a resistive thermometer.
Extreme Condition Capability: The system successfully generated and controlled temperatures exceeding 1000 K within the sample space while maintaining high pressure (tested up to 3.1 GPa).
BDD Component Stability: The BDD heater, thermometer, and electrodes demonstrated excellent stability and reusability, surviving high-temperature and high-pressure cycles without degradation.
Superconductor Annealing: High-pressure annealing of La(O,F)BiS₂ single crystals successfully enhanced the critical temperature (T_c) from 3 K to 8 K, with the enhanced phase successfully quenched to ambient pressure.
Novel Synthesis: The DAC was used for the high-pressure synthesis of the layered superconductor EuFBiS₂, confirming a T_c of 8.6 K and demonstrating a drastic reduction in sample resistance (over three orders of magnitude).
In-Situ Analysis: The transparent diamond anvils allow for simultaneous in-situ analysis, including electrical transport measurements, and potential X-ray or laser analyses during compression and heating.

Technical Specifications

Parameter	Value	Unit	Context
Maximum Sample Temperature	>1000	K	Estimated temperature achieved in the sample space during heating tests (confirmed by radiation thermometer).
Maximum Test Pressure	3.1	GPa	Pressure used for the high-pressure synthesis of EuFBiS₂.
BDD Thermometer Calibration Limit	800	K	Limit of reliable temperature measurement due to saturation of the heavily doped BDD R-T curve.
Heater/Probe Material	Boron-doped diamond (BDD)	N/A	Homoepitaxially grown film used for all integrated components.
La(O,F)BiS₂ T_c (As-grown)	3	K	Initial critical temperature of the single crystal.
La(O,F)BiS₂ T_c (Annealed)	8	K	Enhanced T_c achieved after high-pressure annealing and quenched to ambient pressure.
EuFBiS₂ T_c (Synthesized)	8.6	K	Critical temperature observed after high-pressure synthesis at 3.1 GPa and 900 K.
Resistance Measurement Method	Standard Four-Probe	N/A	Used for measuring sample and BDD thermometer resistance.
Backup Plate Materials Tested	Si₃N₄, Al₂Si₄O₁₀(OH)₂, ZrO₂	N/A	Materials selected based on mechanical hardness and thermal conductivity.

Key Methodologies

The DAC platform integrates BDD components for precise control and measurement under extreme conditions.

BDD Component Fabrication:
- BDD films were homoepitaxially grown onto the diamond anvil surface.
- Patterning of the probes, heater, and thermometer was achieved using electron beam lithography combined with microwave plasma-assisted chemical vapor deposition (CVD).
Temperature Calibration:
- The BDD thermometer resistance-temperature (R-T) relationship was established using a tube furnace under N₂ gas flow to prevent diamond oxidation.
- A thermocouple placed near the anvil served as the reference for calibration up to 800 K.
DAC Assembly and Pressure Control:
- Diamond anvils were mounted onto backup plates (e.g., Si₃N₄).
- A SUS316 stainless steel gasket and cubic boron nitride (cBN) pressure-transmitting medium were used.
- Pressure was determined at room temperature using the ruby fluorescence method.
Resistive Heating and Measurement:
- Temperature control was achieved by tuning the input power supplied to the BDD resistive heater.
- The circuit included a shunt resistor to monitor current flow to the heater.
- In-situ electrical transport measurements of the sample resistance were performed using the BDD probes via the standard four-probe method during compression and heating.
High-Pressure Synthesis/Annealing Examples:
- La(O,F)BiS₂ Annealing: Single crystal was annealed up to 1100 K under 0.7 GPa, resulting in a change from semiconducting to metallic behavior and quenching of the enhanced T_c (8 K) phase to ambient pressure.
- EuFBiS₂ Synthesis: Starting materials were heated up to 900 K and held for 3 minutes under 3.1 GPa, successfully synthesizing the superconducting phase (T_c = 8.6 K).

Commercial Applications

The developed DAC technology, leveraging robust BDD components for high P/T control and in-situ measurement, is highly relevant to several advanced materials and instrumentation fields.

Superconductor Research and Development:
- Synthesis and exploration of novel high-T_c superconductors, particularly metal hydrides and BiS₂-based layered compounds, which require extreme P/T conditions.
- Optimization of synthesis pathways for practical superconductors used in energy storage, magnetic resonance imaging (MRI), and high-speed transport.
Extreme Environment Instrumentation:
- Fabrication of highly stable, reusable BDD sensors (heaters, thermometers, and electrodes) for use in high-pressure physics, geophysics, and materials science research under megabar conditions.
In-Situ Kinetic Analysis:
- Platforms for monitoring chemical reactions and phase transitions in real-time under combined high pressure and high temperature, crucial for understanding material formation kinetics.
Functional Materials Synthesis:
- Controlled synthesis of materials requiring specific high-P/T processing, such as ultra-hard materials, novel ceramics, and high-performance semiconductors, where precise temperature control is critical.
Diamond Technology:
- Demonstration of advanced BDD film fabrication techniques (CVD and lithography) for integrating complex electronic functions directly onto diamond substrates.

View Original Abstract

Temperature and pressure are essential parameters in the synthesis, evaluation, and application of functional materials. This study proposes the addition of a heating function to a high-pressure diamond anvil cell (DAC) with in situ measurement probes. The proposed DAC allows for simultaneous control of temperature and pressure within the sample space and can be used to synthesize functional materials under extreme conditions. The various components, namely, the heater, thermometer, and measurement probes, were fabricated with a boron-doped diamond epitaxial film and could be repeatedly used. The developed DAC was used to conduct the high-pressure annealing of a La(O,F)BiS2 single crystal and the high-pressure synthesis of EuFBiS2 superconductors. The proposed technique shows promise for further exploration of superconductors to broaden the research field.

Tech Support

Original Source

DOI: https://doi.org/10.1063/5.0059705

References

2004 - Superconducting materials for large scale applications [Crossref]
2004 - Development of new types of DI-BSCCO wire
2015 - Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system [Crossref]
2016 - Crystal structure of the superconducting phase of sulfur hydride [Crossref]
2019 - Superconductivity of pure H3S synthesized from elemental sulfur and hydrogen [Crossref]
2019 - Superconductivity at 250 K in lanthanum hydride under high pressures [Crossref]
2019 - Evidence for superconductivity above 260 K in lanthanum superhydride at megabar pressures [Crossref]
2020 - Superconductivity at 161 K in thorium hydride ThH10: Synthesis and properties [Crossref]