高感度?高信頼性TMR磁気センサの開発

摘要

We developed magnetic sensor devices based on magnetic tunnel junctions(MTJs)for monitoring electric currents in automobiles.Magnetic sensors for current monitoring should have a wide dynamic range and very small nonlinearity.We achieved both wide dynamic ranges of more than ±2.5 kOe and small nonlinearity below 0.1%by using CoFeB/MgO/CoFeB-MTJ with a perpendicularly magnetized synthetic antiferro-magnetic reference layer.We also successfully explain the performance of the developed MTJ-based sensors with a simple model based on the Stoner-Wohlfarth and Slonczewski models,and this model gives us a guideline for designing MTJ-based sensors.The developed MTJ-based sensors with a wide dynamic range and small nonlinearity will be promising candidates for highly reliable sensors for monitoring electric currents.