Project Summary
The long-term objective of this project is to develop a revolutionary quantum mechanical solid-state
magnetometer designed to non-invasively detect femtoTesla (fT) scale magnetic fields derived from the brain’s
electrical activities during natural human experiences. The project has been designed to address the vision of
the NIH Brain Initiative: Transformative Brain Non-invasive Imaging Technology Development. The core
component of the magnetometer is a quantum-based magnetic tunnel junction (MTJ), a nanoscale sensing
device with potentially unprecedented sensitivity and performance. Through a series of steps and
interdisciplinary collaboration, this project is expected to increase the sensitivity of the current MTJs by several
orders of magnitude and to develop triaxial MTJ sensors capable of recording the brain's magnetic fields with
the highest information density. Once the desired sensitivity is achieved, the project will build a whole-head
300-channel magnetoencephalographic (MEG) system based on MTJs, which can operate fully untethered,
without the need for an expensive magnetically shielded room or nulling coils. By design, the sensors will be
immune to natural head motion, further enabling the system to function in natural environment. The project will
address several challenges in designing and producing sensors that can detect magnetic fields as low as 50
fT. First, the project will improve the detectability of current prototype sensors by several orders of magnitude
by using a series of innovative approaches in sensor design, atomic engineering, fabrication, and noise
reduction. Second, the project will design and package triaxial sensors that can simultaneously measure
tangential and radial magnetic fields. Third, the project will reduce the size of the sensors by more than five
times compared to other technologies, so that more sensors can be implemented on a full-head helmet to
improve spatial resolution and localization. Finally, and importantly, the project will increase the field dynamic
range of the sensors over the technologies based on OPM (optically pumped magnetometer) and SQUID
(superconducting quantum interference device), so that the MTJ-MEG system can operate without the need of
magnetic shielding to allow real-world applications. Once these groundbreaking MTJ sensors are developed,
the project will integrate the MTJ-MEG system architecture and make it available for verifying performance
versus competing technologies. The project will use the MTJ-MEG system to assess brain related signals
during sensory stimulation, cognitive processing, and motor actions. If successful, this project will develop a
transformative MTJ-MEG system with unpresented levels of performance to produce a dynamic picture of the
brain under natural settings covering the whole lifespan.
