What’s in News:

• Researchers from the Indian Institutes of Technology (IIT) at Mumbai and Kharagpur have built a microscope that can image magnetic fields within microscopic two-dimensional samples that change over milliseconds.
• This is the first time that such a tool has been built to image magnetic fields that change within milliseconds. 

Application

• This has a huge potential for scientific applications, such as in measuring biological activity of neurons and dynamics of vortices in superconductors.
• The ideal frame rate to capture a changing magnetic field is one that captures data at twice the frequency of the changing field. Signals in nature exhibit a range of frequencies — magnetism in geological rock samples and rare earth magnets can be constant over months; magnetic nanoparticle aggregation inside living cells takes place in minutes; action potentials in neurons are fast, taking milliseconds, whereas precession of atomic spins in complex molecules takes only microseconds. The instrument that this team has built works in the millisecond range. 
• The key aspect of this sensor is a “nitrogen vacancy (NV) defect centre” in a diamond crystal. Such NV centres act as pseudo atoms with electronic states that are sensitive to the fields and gradients around them (magnetic fields, temperature, electric field and strain).

 Reference

https://www.thehindu.com/sci-tech/science/quantum-diamond-microscope-to-image-magnetic-fields/article65538129.ece