Imaging magnetic transition of magnetite to megabar pressures using quantum sensors in diamond anvil cell
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2024-10-14 |
| Journal | Nature Communications |
| Authors | Mengqi Wang, Yu Wang, Zhixian Liu, Ganyu Xu, Bo Yang |
| Institutions | Chinese Academy of Sciences, University of Science and Technology of China |
| Citations | 15 |
| Analysis | Full AI Review Included |
Technical Analysis: Megabar Pressure Quantum Sensing using NV Centers in Diamond Anvil Cells
Section titled âTechnical Analysis: Megabar Pressure Quantum Sensing using NV Centers in Diamond Anvil CellsâThis document analyzes the recent publication on utilizing Nitrogen-Vacancy (NV) centers in diamond anvils for in-situ magnetic imaging at megabar pressures, highlighting 6CCVDâs capabilities to supply and customize the critical Single Crystal Diamond (SCD) materials required for this advanced quantum sensing technology.
Executive Summary
Section titled âExecutive Summaryâ- Breakthrough Sensing: Developed a robust in-situ magnetic detection technique using NV quantum sensors integrated into a Diamond Anvil Cell (DAC).
- Extreme Pressure Performance: Achieved stable, high-sensitivity magnetic measurements up to 130 GPa, overcoming previous limitations related to stress-induced degradation of NV center properties.
- Stress Modulation Strategy: Performance was maintained by modulating uniaxial stress along the NV axis, specifically utilizing (111)-cut Single Crystal Diamond (SCD) anvils to minimize detrimental stress components ($\sigma_{\perp}$).
- High Sensitivity & Resolution: Demonstrated high magnetic sensitivity (~1”T/âHz) and sub-microscale spatial resolution, enabling the investigation of nanoscale single-domain grains under extreme conditions.
- Application Success: Successfully imaged the macroscopic magnetic transition of magnetite (Fe3O4) across the megabar range, observing transitions from ferrimagnetic ($\alpha$-Fe3O4) to weak ferromagnetic ($\beta$-Fe3O4) and finally to paramagnetic ($\gamma$-Fe3O4).
- Future Impact: This technique is immediately applicable to high-pressure, high-temperature studies, including the direct detection of the Meissner effect in superhydride superconductors.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental results demonstrating the performance of the NV quantum sensors under extreme pressure:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Maximum Pressure Achieved | 130 | GPa | Stable NV sensing performance |
| Magnetic Detection Sensitivity | ~1 | ”T/âHz | Achieved at megabar pressures |
| Spatial Resolution | Sub-microscale | N/A | Estimated from optical diffraction limit |
| ODMR Contrast Enhancement | ~30 | % | Observed at 130 GPa (compared to 1.5 GPa) |
| ODMR Linewidth (Narrowed) | ~20 | MHz | Five-fold reduction compared to previous work |
| NV Center Depth | ~9 | nm | Distance from anvil surface |
| Nitrogen Ion Implantation Energy | 6 | keV | Used for NV layer creation |
| Nitrogen Ion Implantation Dose | 1 x 1013 | /cm2 | Used for NV layer creation |
| Diamond Anvil Material | HPHT Type-IIa | N/A | Non-fluorescent Single Crystal Diamond (SCD) |
| Diamond Anvil Orientation | (111)-cut | N/A | Used to minimize $\sigma_{\perp}$ stress component |
| Fe3O4 Sample Size | 4 x 5 x 1 | ”m | Single crystal magnetite sample dimensions |
Key Methodologies
Section titled âKey MethodologiesâThe successful implementation of the NV quantum sensor at megabar pressures relied on precise material engineering and DAC setup:
- Diamond Anvil Selection: HPHT Type-IIa (Non-fluorescent) Single Crystal Diamond (SCD) was used to minimize optical background noise.
- Crystal Orientation Control: Anvils were cut and polished to the (111) orientation to ensure the uniaxial stress component ($\sigma_{\perp}$) perpendicular to the NV axis was minimized, thereby preserving the spin-triplet state (S=1) necessary for magnetic detection.
- Custom Culet Dimensions: Anvils featured 100 ”m and 150 ”m diameter culets, demonstrating the need for precise, small-scale diamond machining.
- NV Center Fabrication: Shallow NV centers were created via low-energy 14N+ ion implantation (6 keV energy, 1 x 1013/cm2 dose) followed by high-temperature vacuum annealing (1000 °C). This resulted in a highly concentrated NV layer approximately 9 nm deep.
- Microwave Integration: A Platinum (Pt) wire was compressed between the gasket and anvil pavilion facets, serving as the microwave radiation guide for coherent spin control.
- Pressure Environment: A BeCu symmetric DAC was used with a Rhenium gasket. KCl served as the pressure-transmitting medium (PTM) to maintain a quasi-hydrostatic environment.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to support the replication and extension of this high-pressure quantum sensing research by providing the necessary high-specification MPCVD diamond materials and customization services.
| Research Requirement | 6CCVD Applicable Materials & Services | Technical Value Proposition |
|---|---|---|
| High-Purity Diamond Anvils | Optical Grade Single Crystal Diamond (SCD) | Our MPCVD SCD offers superior purity and low intrinsic nitrogen content, ensuring the non-fluorescent background required for high-contrast Optically Detected Magnetic Resonance (ODMR) measurements at extreme pressures. |
| Specific Crystal Orientation | Custom SCD Orientation (e.g., (111) or (100)) | We provide SCD plates and wafers with precise crystallographic orientation control, critical for minimizing stress-induced spin-crossover effects and maximizing NV center magnetic sensitivity up to 130 GPa. |
| Shallow NV Layer Creation | SCD Wafers Optimized for Ion Implantation | 6CCVD supplies SCD substrates with ultra-low surface roughness (Ra < 1 nm) and controlled nitrogen concentration, ideal for subsequent shallow ion implantation (6 keV 14N+) and high-temperature annealing processes. |
| Custom Anvil/Plate Dimensions | SCD Plates up to 500 ”m Thickness; Substrates up to 10 mm | We offer custom dimensions and laser cutting services to meet the exact requirements for DAC culets (e.g., 100 ”m or 150 ”m diameter) and substrate thickness. |
| Microwave Guide Integration | Custom Metalization Services (Pt, Ti/Pt/Au) | We offer in-house metalization capabilities, including Platinum (Pt) deposition, enabling researchers to integrate microwave transmission lines directly onto the diamond anvil surface for coherent spin manipulation. |
| Polycrystalline Diamond (PCD) Potential | High-Purity MPCVD Polycrystalline Diamond (PCD) | For applications requiring larger sensing areas or lower cost, our PCD wafers (up to 125 mm diameter, Ra < 5 nm) can be utilized for magnetic sensing in lower-pressure regimes or for non-DAC related quantum experiments. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in the material science of quantum defects and high-pressure physics. We offer comprehensive engineering consultation to assist researchers in selecting the optimal diamond material specifications (purity, orientation, thickness) for complex projects, including:
- Replicating high-pressure quantum sensing experiments.
- Developing NV-based magnetometers for Meissner effect detection in novel superconductors (e.g., super hydrides).
- Optimizing diamond substrates for advanced ion implantation and annealing recipes.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Abstract High-pressure diamond anvil cells have been widely used to create novel states of matter. Nevertheless, the lack of universal in-situ magnetic measurement techniques at megabar pressures makes it difficult to understand the underlying physics of materialsâ behavior at extreme conditions, such as high-temperature superconductivity of hydrides and the formation or destruction of the local magnetic moments in magnetic systems. Here, we break through the limitations of pressure on quantum sensors by modulating the uniaxial stress along the nitrogen-vacancy axis and develop the in-situ magnetic detection technique at megabar pressures with high sensitivity ( $$\sim 1{{{\rm{\mu }}}}{{{\rm{T}}}}/\sqrt{{{{\rm{Hz}}}}}$$ <mml:math xmlns:mml=âhttp://www.w3.org/1998/Math/MathMLâ> <mml:mo>~</mml:mo> <mml:mn>1</mml:mn> <mml:mi>ÎŒ</mml:mi> <mml:mi>T</mml:mi> <mml:mo>/</mml:mo> <mml:msqrt> <mml:mrow> <mml:mi>Hz</mml:mi> </mml:mrow> </mml:msqrt> </mml:math> ) and sub-microscale spatial resolution. By directly imaging the magnetic field and the evolution of magnetic domains, we observe the macroscopic magnetic transition of Fe 3 O 4 in the megabar pressure range from ferrimagnetic ( α -Fe 3 O 4 ) to weak ferromagnetic ( ÎČ -Fe 3 O 4 ) and finally to paramagnetic ( Îł -Fe 3 O 4 ). The scenarios for magnetic changes in Fe 3 O 4 characterized here shed light on the direct magnetic microstructure observation in bulk materials at high pressure and contribute to understanding magnetism evolution in the presence of numerous complex factors such as spin crossover, altered magnetic interactions and structural phase transitions.