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 has a huge potential for scientific applications, such as in measuring biological activity of neurons and dynamics of vortices in superconductors. The work, led by IIT Bombay professor Kasturi Saha, from the Department of Electrical Engineering, has been published in Scientific Reports. This is the first time that such a tool has been built to image magnetic fields that change within milliseconds.
Capturing change
Prof. Saha explains that 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.
