By Kapildeb Ambal, Wichita State University, Department of Physics
Scanning nitrogen vacancy (NV) magnetometry is a measurement technique that combines scanned probe microscopy (SPM) with optically detected magnetic resonance (ODMR) to image magnetic field distribution with high spatial resolution (<50 nm). This technique advances our understanding of nanomagnetism at surfaces from condensed matter physics to cell biology.
Scanning NV magnetometry “relies on a single, optically-readable defect spin [i.e., an NV center] embedded in a sharp diamond tip that is scanned over the sample of interest” and commonly is applied in two different ways. The first type of measurement, called a pulsed measurement (such as relaxometry), is extremely sensitive but very slow. Continuous wave (CW) scanning NV magnetometry, meanwhile, is less sensitive but is relatively fast, recording a single data point within a few seconds.
When scanning NV magnetometry was first developed about a decade ago, researchers required deep expertise to apply the technique. Only recently has the instrumentation required become more intuitive to use and more commercially available, greatly expanding the opportunities for scanning NV magnetometry’s application in numerous areas of research, and progress continues. That said, it is relatively simple to build a scanning NV magnetometry microscope from a resonant probe AFM. In many ways, developing a custom instrument is desirable since scanning NV magnetometry is useful across a range of applications with differing instrument requirements.