Tsuyoshi Uchiyama
Nagoya University, Japan
Title: Development of highly sensitive micro magnetic sensor for biomagnetic field measurement utilizing magneto-impedance element
Biography
Biography: Tsuyoshi Uchiyama
Abstract
Magnetization dynamics by pulse excitation in amorphous wire is limited in the surface layer by skin effect due to magnetic rotation. We have constituted highly sensitive linear micro magnetic field sensors utilizing Off-diagonal Magneto-Impedance (MI) effect. Recently we have succeeded in producing pico-Tesla (10-8Oe) resolution MI sensors due to ultra-low intrinsic magnetic noise of amorphous wire. Superconducting quantum interference deice (SQUID) have ultrasensitive, which have been utilized for biomagnetic signals. For example, magnetocardiography (MCG) is a noninvasive technology that measures the magnetic field of the heart. It was developed for general-purpose use as a noninvasive, noncontact diagnostic tool for detecting obstructive coronary artery disease (CAD). The SQUID has been also used to measure the human brain. The application of brain signals detection was developed in various fields. In medicine area, it could be implemented in such as brain injury inspection, diagnosis of neocortical epilepsy, telemedicine or cognitive functions research. And with advances in sensing technology, neuroprosthetics applications based on brain computer interfacing (BCI) could be improved and used to restore damaged hearing, sight or movement. Comparing with the SQUIDs, MI sensor is smaller, lower cost and no need for low temperature operation. The brainwaves of mean N100 and P300 ERP elicited by audio stimuli have been measured by MI sensor. Brainwave measurement results of MI sensor will be presented and the results will be compared with SQUID\\\'s or EEG\\\'s results. The measurement results for MCG by MI sensor also will be presented.