MgO magnetic tunnel junction (MTJ) sensors with spin-valve-like sensing layers of Ir22Mn78 (6)/Ni80Fe20 (tNiFe20-70)/Ru (0.9)/Co40Fe40B20 (3) (unit: nm) have been fabricated. A linear field dependence of magnetoresistance for these MTJ sensors was obtained by carrying out a two-step field annealing process. The sensitivity and linear field range can be tuned by varying the thickness of NiFe layer and annealing temperature, and a high sensitivity of 37%/mT has been achieved in the MTJ sensors with 70nm NiFe at the optimum annealing temperature of 230°C. Combining the spin-valve-like sensing structure and a soft magnetic NiFe layer, MTJ sensors with relatively wide field sensing range have been achieved and could be promising for showing high sensitivity magnetic field sensing applications.
ASJC Scopus subject areas
- Physics and Astronomy(all)