Systematic Investigation on Correlation Between Sensitivity and Nonlinearity in Magnetic Tunnel Junction for Magnetic Sensor

We fabricated magnetic tunnel junctions (MTJs) with a perpendicularly magnetized Co-Fe-B sensing layer for magnetic sensor applications exhibiting a linear tunneling magnetoresistance behavior, and systematically investigated correlation between sensitivity and nonlinearity in the MTJs. The experimental results in the MTJs annealed at different temperatures with various thicknesses and compositions of the Co-Fe-B sensing layer were compared with the simple calculation based on the Stoner-Wohlfarth model, which predicts the tradeoff relationship between the sensitivity and the nonlinearity. We found the clear tradeoff correlation between them regardless the annealing temperature and the composition of the Co-Fe-B sensing layer. These results show us a guideline for designing the sensing properties of magnetic sensors based on MTJs.