In magnetic tunnel junctions (MTJs), the resistance changes by external magnetic field through tunnel magnetoresistance (TMR) effect and MTJs can be applied to magnetic field sensors. To detect a small bio-magnetic field, we have to develop MTJs with high sensitivity (=TMR/2Hk, Hk: magnetic anisotropy field) of more than 100%/Oe, which is two digit larger than that of actual devices. In this work, MTJs with a low Hk CoFeSiB amorphous electrode was fabricated to realize such a highly sensitive magnetic sensor. After optimizing the preparation condition of CoFeSiB, a very high sensitivity of 40%/Oe was obtained. The result came much closer to our goal.
|Journal||Transactions of Japanese Society for Medical and Biological Engineering|
|Publication status||Published - 2014 Aug 17|
- Bio-magnetic field
- Magnetic field sensor
- Magnetic tunnel junction