1. Research background and goals

It has been found that the nitrogen-vacancy complex center (diamond NV center) in diamond has high performance as a probe for sensing spins existing in the surrounding environment.

We have developed a novel scanning spin probe microscope with a diamond NV center (diamond spin probe microscope) that uses the diamond NV center as a probe, and realize the detection of single electron spins using this. Furthermore, the detection of nuclear spins. Work on research with a view to.

2. Major research results and impact on society and academia

A confocal microscope device that reads out a single spin existing at the NV center (center of the nitrogen vacancy complex) in the diamond rod, and a crystal transducer type atomic force microscope (AFM) device that uses this diamond rod as a probe. We have developed a fused scanning diamond spin probe microscope.

The spin sensor scanning probe developed in this research will ultimately realize local measurement of the dynamics of spins existing in the surrounding environment with the sensitivity and spatial resolution of single electron spins and single nuclear spins if performance is pursued. This has the potential to clarify spin dynamics information obtained as average information in samples in technologies such as electron spin resonance (ESR) and nuclear porcelain resonance (NMR) at a single spin level. It will be a useful tool that can contribute to spintronics devices and life science fields, such as the realization of microscopic spin state measurement of spins in magnetic materials and nuclear magnetic resonance (NMR) measurement in one cell.

The NV center (Nitrogen-vacancy center) has a structure in which adjacent C atoms are missing when N atoms are injected into the diamond face-centered cubic lattice to replace C atoms.

   The electron spin contained in this NV center is currently being researched all over the world as being capable of performing highly sensitive magnetic measurements at room temperature, room temperature, and atmospheric pressure, and our laboratory is also pursuing this novel phenomenon.

JAIST owns an ion implanter (GIFS), which is rare in Japan, to create an NV center inside a diamond.

It is possible to irradiate diamond directly with N⁺ ion to create an NV center in a region on the order of several nanometers.

High Power High temperature Diamond:

15N Irradiation temperature 600° implantation

35keV 1.2×1011/cm2

Optically Detected Magnetic Resonance (ODMR)

A method of optically detecting a magnetic resonance phenomenon. In this study, the magnetic resonance of the NV center spin is detected by measuring the change in fluorescence intensity due to the application of microwaves excited and generated by the injection of a 532 nanometer laser beam.

The electron spins excited by the green laser (532 nm) fluoresce red during the relaxation process. At this time, by adding microwave energy, the electrons that were in the 0 level shift to the 1 level. Since the electrons transferred to 1 pass through a process that does not fluoresce stochastically, the fluorescence becomes weak.

Furthermore, since ms = ± 1 is Zeeman split in proportion to the external magnetic field strength due to the influence of the external magnetic field, the external magnetic field strength can be detected from the frequency of the point where the red light brightness decreases.