Probing Local Pressure Environment in Anvil Cells with Nitrogen-Vacancy (N-V−) Centers in Diamond
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2020-02-18 |
| Journal | Physical Review Applied |
| Authors | Kin On Ho, Man Yin Leung, Yaxin Jiang, Kin Pong Ao, Wei Zhang |
| Institutions | Chinese University of Hong Kong, Chinese University of Hong Kong, Shenzhen |
| Citations | 31 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled “Executive Summary”This study introduces and validates a novel methodology for mapping local pressure environments within high-pressure cells using Nitrogen Vacancy (NV-) centers in nanodiamonds (NDs) as quantum sensors.
- High Spatial Resolution: Achieved approximately 1 µm spatial resolution for pressure mapping, a significant improvement over traditional bulk ruby fluorescence methods, enabling detailed study of pressure inhomogeneity.
- Wide Operating Range: The NV- sensor was successfully benchmarked and utilized across a broad range of conditions, spanning pressures up to 63 kbar and temperatures from 6 K to 295 K.
- Pressure Coefficient Calibration: The longitudinal Zero-Field Splitting (ZFS) pressure dependence was precisely calibrated against ruby spectroscopy, yielding a coefficient of dD/dP = 1.49 ± 0.02 MHz/kbar.
- Solidification Tracking: The method successfully tracked the pressure-induced solidification of Daphne oil 7373 (onset ~28 kbar) by monitoring the increase in spectral linewidth and the standard deviation of local pressure measurements.
- Inhomogeneity Quantification: Demonstrated the ability to quantify pressure gradients and local shear stress (via the transverse ZFS, E), revealing that pressure distribution is highly sensitive to anvil alignment and the sequence of pressure application.
- Cryogenic Compatibility: NV- centers proved ideal for cryogenic studies (below 30 K) due to their robust performance and negligible temperature dependence on the ZFS, simplifying pressure calibration at low temperatures.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Sensor Material | Nanodiamonds (NDs) | - | Containing NV- centers |
| ND Particle Size | 1 | µm | Used for high-resolution spatial mapping |
| Nitrogen Concentration | 3 | ppm | Concentration within the NDs |
| Pressure Coefficient (dD/dP) | 1.49 ± 0.02 | MHz/kbar | Longitudinal ZFS shift calibration |
| ZFS (D) at Ambient P/T | 2.87 | GHz | Zero-Field Splitting frequency |
| Maximum Pressure Tested | 63.0 | kbar | Achieved in Daphne oil 7373 medium |
| Temperature Range Tested | 6 to 295 | K | Cryogenic to Room Temperature |
| Spatial Resolution (Confocal) | ~1 | µm | Best resolution for local ODMR measurement |
| Pressure Medium | Daphne oil 7373 | - | Used for solidification study |
| Solidification Critical Pressure | ~28 | kbar | Onset pressure for Daphne oil 7373 |
| Gasket Hole Diameter | 400 | µm | Confined sample/medium region |
| Excitation Wavelength | 520 | nm | Laser diode used for NV- initialization/readout |
| Ruby R1 Sensitivity (P) | 0.364 | A/kbar | Traditional pressure sensor comparison |
Key Methodologies
Section titled “Key Methodologies”- Pressure Cell Configuration: Utilized a Diamond Anvil Cell (DAC) setup incorporating a 200 µm diameter microcoil for microwave (MW) transmission, enabling Electron Spin Resonance (ESR) measurements under high pressure.
- Sensor Integration: 1 µm nanodiamonds (NDs) were drop-casted onto the anvil surface or a dummy sample inside the 400 µm gasket hole, alongside a ruby chip for initial pressure calibration.
- Optical Readout: Two setups were employed: a simple fluorescence microscopy setup (for benchmarking against ruby) and a confocal microscopy setup (using a galvo mirror) to achieve high spatial resolution (down to ~1 µm) for mapping individual NDs.
- Pressure Calibration: Average pressure was determined using the R1 peak shift of the ruby fluorescence spectrum. This was used to calibrate the NV- longitudinal ZFS (D) shift, establishing the dD/dP coefficient.
- Local Pressure Mapping: Optically Detected Magnetic Resonance (ODMR) spectra were measured for multiple individual NDs across the pressurized region. Local pressure was calculated from the center frequency shift of the ODMR resonances.
- Solidification Analysis: The onset of solidification was determined by monitoring the increase in ODMR spectral linewidth (due to spatial inhomogeneity within the particle) and the standard deviation (SD) of pressure values across the cell.
- Temperature Decoupling: For cryogenic measurements (6 K to 10 K), pressure effects were isolated from temperature effects by leveraging the near-zero temperature dependence of the NV- ZFS (D) below 30 K.
Commercial Applications
Section titled “Commercial Applications”- Quantum Sensing and Metrology: NV- centers in NDs serve as versatile, robust quantum sensors capable of simultaneous, spatially resolved measurement of pressure, temperature, magnetic fields, and electric fields in extreme environments (high pressure, cryogenic).
- High-Pressure Physics Instrumentation: Integration into DAC systems to provide crucial in-situ pressure distribution maps, necessary for accurate interpretation of bulk measurements (e.g., magnetic susceptibility, quantum oscillations) where pressure uniformity is critical.
- Fluid Dynamics and Rheology: Precise determination of hydrostatic limits and tracking of phase transitions (solidification/freezing) in pressure transmitting media, benefiting research in supercritical fluids and glass transitions.
- Geophysics and Planetary Science: Simulation and study of material behavior under extreme pressures relevant to planetary interiors, requiring accurate local stress and strain mapping.
- Micro- and Nano-Mechanics: Use of the transverse ZFS (E) as a highly sensitive indicator to map local shear stress and strain gradients within materials, aiding in the design and failure analysis of micro-components.
View Original Abstract
Important discoveries have frequently been made through the studies of matter\nunder high pressure. The conditions of the pressure environment are important\nfor the interpretation of the experimental results. Due to various restrictions\ninside the pressure cell, detailed information relevant to the pressure\nenvironment, such as the pressure distribution, can be hard to obtain\nexperimentally. Here we present the study of pressure distributions inside the\npressure medium under different experimental conditions with NV centers in\ndiamond particles as the sensor. These studies not only show a good spatial\nresolution, wide temperature and pressure working ranges, compatibility of the\nexisting pressure cell design with the new method, but also demonstrate the\nusefulness to measure with these sensors as the pressure distribution is\nsensitive to various factors. The method and the results will benefit many\ndisciplines such as material research and phase transitions in fluid dynamics.\n