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Recently, magnetic sensors are being used in various applications such as autonomous vehicles and IoT. For the application of such magnetic sensors, the consistent performance of sensors is important. In particular, Planar Hall Magneto Resistance (PHMR) sensors have high signal sensitivity and low offset characteristics. However, it shows indiscriminately different offset characteristics during the sensor manufacturing stage. This study investigated the characteristics of the offset voltage and the phase of the characteristic curve in a NIFe/IrMn bilayer structure PHMR sensor, which vary depending on the direction of current application and voltage measurement. By applying an analytical method, we separated the sensor signal to classify the offset voltage characteristics unrelated to magnetoresistance and offset voltage characteristics caused by changes in the magnetoresistance phase. We also analyzed the ratio between signals with AMR characteristics and signals with PHMR characteristics affected by phase changes, as well as changes in sensitivity characteristics of the magnetic sensor. As a result, when the current application direction and voltage measurement direction were adjusted to specific conditions, the output voltage and sensitivity increased. These findings are expected to have implications for optimizing sensor design and manufacturing processes and improving sensor performance.
Fig. 1 A multi-electrode PHMR sensor consisting of 16 electrodes was used to control the directions of the applied current and the measured voltage according to the electrode setting using a switching system to check the sensor characteristics affected by the current distribution area, density and direction, and voltage measurement direction.
Acknowledgements
This paper is funded by the government (Ministry of Trade, Industry and Energy) in 2023. This study was conducted with the support of the National Institute of Industrial Technology Evaluation and Management.
References
[1] H. Gu, X. Zhang, H. Wei, Y. Huang, S. Wei, and Z. Guo, “An overview of the magnetoresistance phenomenon in molecular systems,” Chemical Society Reviews, vol. 42, no. 13. Royal Society of Chemistry (RSC), p. 5907, 2013. doi: 10.1039/c3cs60074b.
