Visualization of the Meissner Effect Using Miniaturized Quantum Magnetometers

At a Glance

Metadata	Details
Publication Date	2025-09-05
Journal	Applied Sciences
Authors	Wookyoung Choi, Chanhu Park, Jaebum Park, Dongkwon Lee, Myeongwon Lee
Institutions	LG (South Korea), Korea University
Analysis	Full AI Review Included

Technical Documentation & Analysis: Diamond NV Quantum Magnetometry

Executive Summary

This research successfully demonstrates a novel, non-destructive method for visualizing the Meissner effect using a miniaturized scanning quantum magnetometer based on Nitrogen-Vacancy (NV) centers in diamond. This work validates the critical role of high-quality CVD diamond in next-generation quantum sensing applications.

Core Achievement: Direct visualization and mapping of static magnetic field expulsion (Meissner effect) in a high-T_c superconductor (YBCO) using a diamond NV ensemble sensor.
Material Requirement: The sensor utilizes a Type 1b diamond plate (3 mm x 3 mm x 0.3 mm) with an NV density of ~10¹³/cm³, oriented along the <100> crystal direction.
Operational Advantage: The system operates under ambient, room-temperature conditions, significantly simplifying the experimental setup compared to traditional cryogenic magnetometry.
Advanced Sensing: Vector magnetometry is achieved by analyzing the frequency shifts of four distinct NV crystallographic orientations, allowing for the reconstruction of 3D magnetic field components (B_x, B_y, B_z).
Dual Functionality: The NV center simultaneously acts as a magnetic sensor (via Zeeman splitting) and a temperature sensor (via the temperature-dependent Zero-Field Splitting, D(T)).
Commercial Relevance: The technique is highly practical for educational demonstrations, early-stage superconductivity diagnostics, and non-invasive characterization of diverse superconducting geometries (wires, tapes, bulk samples).

Technical Specifications

The following hard data points were extracted from the experimental setup and results:

Parameter	Value	Unit	Context
Diamond Type	Type 1b (Ensemble NV)	N/A	Quantum sensor material
Diamond Dimensions	3 x 3 x 0.3	mm	Plate size (Length x Width x Thickness)
Crystal Orientation	<100>	N/A	Required for NV axis alignment
NV Density	~10¹³	cm^-3	Concentration of sensing defects
Operating Temperature	Ambient (Room)	°C	Sensor operation condition
Laser Wavelength	532	nm	Excitation source for PL
Laser Power	~24	mW	Power delivered to the NV centers
Microwave Frequency	~2.87	GHz	Zero-Field Splitting (ZFS) at RT
Sensor-Sample Separation (h)	1.7, 1.9, 2.1	cm	Vertical distance during scanning
Scanning Area	4.3 x 4.3	cm²	Total area mapped
Scanning Step Size	2.15	mm	Spatial resolution of the scan
Critical Temperature (T_c)	93	K	YBCO superconductor T_c
Temperature Sensitivity (dD/dT)	-74.2	kHz/K	Used for qualitative temperature monitoring

Key Methodologies

The experiment relies on precise material engineering and advanced quantum sensing techniques to achieve room-temperature magnetic field mapping.

Diamond Sensor Fabrication: A Type 1b diamond plate (<100> oriented, 3 mm x 3 mm x 0.3 mm) containing ensemble NV centers (~10¹³/cm³) is integrated with custom optics (lenses, dichroic filter, photodetector).
Optical Excitation and Readout: A fiber-coupled 532 nm laser excites the NV centers. Photoluminescence (PL) is collected via a GRIN lens and detected after filtering.
Microwave Delivery: A 3 GHz microwave field is delivered via a coaxial cable and an integrated double split-ring resonator to manipulate the NV spin states.
Optically Detected Magnetic Resonance (ODMR): Electron spin resonances are detected by monitoring the reduction in PL signal when the microwave frequency matches the spin transition (m_s = 0 to m_s = ±1). Lock-in detection is used to improve the signal-to-noise ratio.
Vector Magnetometry: By analyzing the frequency shifts of the four distinct crystallographic NV orientations ([111], [111], [111], and [111]), the three-dimensional magnetic field components (B_x, B_y, B_z) are reconstructed.
Temperature Monitoring: The common frequency shift (f_c) of the m_s = ±1 states relative to m_s = 0 is tracked. Since the Zero-Field Splitting D(T) is temperature-dependent, this provides qualitative, simultaneous temperature monitoring of the YBCO surface via thermal radiation.
Scanning and Data Acquisition: A custom-built 2D scanning stage driven by stepper motors positions the sensor above the YBCO sample (cooled by liquid nitrogen) at precise vertical distances (h = 1.7 cm to 2.1 cm) to map the magnetic field profiles.

6CCVD Solutions & Capabilities

The successful implementation of this miniaturized quantum magnetometer hinges on the availability of high-quality, precisely engineered diamond material. 6CCVD is uniquely positioned to supply the necessary Single Crystal Diamond (SCD) substrates and customization services required to replicate, scale, and advance this research.

Applicable Materials

To replicate or extend the high-resolution vector magnetometry demonstrated in this paper, researchers require high-purity, low-strain SCD material with controlled NV incorporation.

6CCVD Material	Specification	Relevance to Research
High-Purity SCD (Electronic Grade)	<100> or <111> orientation, Low Strain	Ideal base material for high-coherence NV centers via post-growth implantation or in-situ doping.
NV-Engineered SCD	Controlled Nitrogen concentration (PPM to PPB)	Enables precise tuning of ensemble NV density (e.g., the required ~10¹³/cm³) for optimal signal-to-noise ratio and spatial resolution.
Optical Grade SCD	Ra < 1 nm polishing, high transmission	Essential for maximizing laser coupling (532 nm) and Photoluminescence (PL) collection efficiency, critical for ODMR sensitivity.

Customization Potential

The experimental setup utilized a specific diamond geometry (3 mm x 3 mm x 0.3 mm) and required precise optical integration. 6CCVD offers comprehensive services to meet these exact engineering needs:

Custom Dimensions and Thickness: 6CCVD can supply SCD plates up to 125 mm in diameter. The required 300 µm thickness is standard, and we offer thicknesses from 0.1 µm up to 500 µm for SCD, ensuring compatibility with miniaturized sensor heads.
Precision Polishing: We guarantee ultra-smooth surfaces (Ra < 1 nm for SCD) on both sides, which is crucial for minimizing scattering losses and maximizing the efficiency of the integrated GRIN lens and optical train.
Integrated Microwave Structures (Metalization): While the paper used an external split-ring resonator, future miniaturization requires integrated microwave delivery. 6CCVD offers in-house metalization services (Au, Pt, Ti, W, Cu) for depositing custom microstrip lines or antenna structures directly onto the diamond surface, enabling more compact and efficient ODMR setups.
Orientation Control: We provide SCD substrates with precise <100> orientation, matching the requirement of this study, or <111> orientation, which is often preferred for maximizing the signal from a single NV axis.

Engineering Support

The successful development of quantum magnetometers requires deep expertise in both material science and quantum physics. 6CCVD’s in-house PhD team specializes in CVD diamond growth and defect engineering. We can assist researchers and engineers with:

Material Selection: Advising on the optimal nitrogen concentration and growth parameters to achieve the desired NV density and coherence time for similar Room-Temperature Quantum Magnetometry projects.
Substrate Preparation: Consulting on surface termination and polishing requirements necessary for subsequent NV creation (implantation or annealing) or direct integration with optical components.
Design for Integration: Providing technical specifications for diamond plates optimized for integration with fiber optics, GRIN lenses, and microwave circuitry.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

The direct visualization of the Meissner effect is achieved by mapping the expulsion of static magnetic fields from a high-TC superconductor, specifically Yttrium Barium Copper Oxide (YBCO). This is accomplished using a miniaturized scanning magnetometer based on an ensemble of nitrogen-vacancy (NV) centers in diamond, operating under ambient room-temperature conditions. By comparing the magnetic field profiles above the YBCO sample at temperatures above and below its critical temperature TC, we observe clear suppression and distortion of the magnetic field in the superconducting state. These observations are consistent with both magnetic simulations and expected characteristics of the Meissner effect. This work introduces a novel and practical method for visualizing the Meissner effect, offering potential applications in educational demonstrations and the diagnostic testing of superconductivity using room-temperature quantum magnetometry.

Tech Support

Original Source

DOI: https://doi.org/10.3390/app15179766

References

1933 - Ein Neuer Effekt Bei Eintritt Der Supraleitfähigkeit [Crossref]
2010 - Scanning SQUID Microscopy of Vortex Clusters in Multiband Superconductors [Crossref]
2000 - Magnetic Force Microscopy of Layered Superconductors [Crossref]
2009 - Imaging Flux Vortices in Type II Superconductors with a Commercial Transmission Electron Microscope [Crossref]
2025 - Studying Critical Parameters of Superconductor via Diamond Quantum Sensors [Crossref]
2014 - Diamond Magnetometry of Superconducting Thin Films [Crossref]
2019 - Mapping Dynamical Magnetic Responses of Ultrathin Micron-Size Superconducting Films Using Nitrogen-Vacancy Centers in Diamond [Crossref]