Nanoscale magnetic tunnel junction sensors with perpendicular anisotropy sensing layer

A nano-scale linear magnetoresistance sensor is demonstrated using magnetic tunnel junctions with an in-plane magnetized reference layer and a sensing layer with interfacial perpendicular anisotropy. We show that the sensor response depends critically on the thickness of the sensing layer since its perpendicular anisotropy is significantly associated with thickness. The optimized sensors exhibit a large field sensitivity of up to 0.02% MR/Oe and a high linear field range of up to 600 Oe. These findings imply that this sensing scheme is a promising method for developing nano-scale magnetic sensors with simple design, high sensitivity, and low power consumption. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4744914]