Coupling a Single Nitrogen-Vacancy Center in Nanodiamond to Superparamagnetic Nanoparticles

Area of Science:

• Quantum sensing
• Nanotechnology
• Materials science

Background:

• Single nitrogen-vacancy (NV) centers in diamond are versatile quantum systems for photon emission and spin qubit applications.
• NV centers exhibit robust room-temperature operation and long spin coherence times, enabling nanoscale sensing.
• Previous work coupled NV centers to various structures, including living cells, for fundamental nanoscale interaction studies.

Purpose of the Study:

• To develop a controlled method for coupling single NV centers in nanodiamonds to superparamagnetic iron oxide nanoparticles.
• To investigate the use of NV-diamond/superparamagnetic-nanoparticle hybrid systems for local nanomagnetometry.
• To explore the potential of these hybrid systems for enhancing the sensitivity of diamond-based nanosensors.

Main Methods:

• Utilized a nanomanipulation technique to precisely couple a single NV center within a nanodiamond to a few-nanometer superparamagnetic iron oxide nanoparticle.
• Employed relaxometry to measure the magnetic noise originating from the superparamagnetic nanoparticle.
• Leveraged the crystal strain-induced separation of NV spin levels (m_s = ±1) to detect the nanoparticle's influence under an applied AC magnetic field.

Main Results:

• Successfully demonstrated controlled coupling between a single NV center and a superparamagnetic nanoparticle.
• Measured the magnetic particle spin-noise and observed its effect on the NV spin levels in the presence of AC magnetic fields.
• Gained detailed insights into the high-frequency behavior of superparamagnetic nanoparticles.

Conclusions:

• The developed nanomanipulation approach enables controlled coupling of NV centers with nanomagnetic particles.
• Superparamagnetic nanoparticles can amplify local magnetic interactions, significantly improving the sensitivity of diamond nanosensors.
• This hybrid system offers a promising platform for investigating complex nanomagnetic assemblies and advancing nanoscale sensing technologies.