SBIR Phase I: Evaluating ADFMR magnetometers for portable, non-invasive functional bioimaging

This SBIR Phase I project examines the feasibility of using magnetic sensors based on Acoustically Driven Ferromagnetic Resonance (ADFMR) for neurological imaging. Information about brain activity is critical to the diagnosis and treatment of a variety of disorders including epilepsy, traumatic brain injury, and Alzheimer's disease. The most powerful non-invasive technique for measuring brain activity, magnetoencephalography (MEG), uses magnetometers that require liquid helium cooling and magnetic shielding to operate. Due to these requirements, current MEG systems are large and expensive, limiting their adoption and accessibility. ADFMR sensors could allow for the measurement of biomagnetic fields without the need for cryogenics and magnetic shielding, dramatically reducing the size, cost, and power consumption of such systems. The portability of this improved technology would allow for functional neuroimaging outside of the carefully controlled imaging suites where it is possible today. This could allow for diagnosis of previously unreachable patients (ie. in the ICU, operating room, or ambulance) as well as the development of new uses for this technology (ie. long-term monitoring, scanning during movement). This improved, portable MEG could also enable the first practical, portable brain-computer interface ? applicable across a wide variety of applications in both defense and consumer sectors. This SBIR Phase I project investigates the ability for ADFMR sensors to measure extremely small magnetic fields, such as those generated by the human brain. The ADFMR phenomenon has been shown to be a much more power and size efficient alternative to traditional methods of exciting ferromagnetic resonance, allowing for its use as a sensing mechanism for chip-scale magnetometers. In the proposed program, a number of methods to improve the performance of current ADFMR devices will be investigated. First, a compact model will be developed to allow for fast modeling of ADFMR devices and their associated detection circuitry. Using the results of this model, devices will be fabricated in order to experimentally validate various mechanisms for the reduction of 1/f noise in the detector circuitry and for the optimization of the ADFMR absorption profile for maximum sensitivity to applied magnetic fields. These sensor elements will initially be tested using standard benchtop characterization equipment. Following a benchtop demonstration, challenges in miniaturizing the full sensor system will be addressed by developing fully integrated magnetometer prototypes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.