Title :
Large Area and Low Aspect Ratio Linear Magnetic Tunnel Junctions With a Soft-Pinned Sensing Layer
Author :
Ferreira, R. ; Paz, E. ; Freitas, P.P. ; Wang, J. ; Xue, S.
Author_Institution :
INL-Int. Iberian Nanotechnol. Lab., Braga, Portugal
Abstract :
Large area MTJs with linear response and very larger sensitivities are needed to fulfill the requirements for the detection of pT/Hz0.5 magnetic fields at low frequency and room temperature. MTJ stacks with soft-pinned sensing layers have been developed and the stack was optimized, providing a tunable soft-pinning field over a large range of values. Sensitivities corresponding to resistance changes of up to 7%/Oe are obtained in patterned MTJs with areas of 20 × 20 μm2 starting from films with high sensitivity soft-pinned layers made from 3.0Co40Fe40B20/0.21Ta/8.0Ni81Fe19/8.0Ir20Mn80.
Keywords :
boron alloys; cobalt alloys; iridium alloys; iron alloys; magnetic sensors; magnetic thin films; magnetic tunnelling; magnetoresistance; manganese alloys; nickel alloys; tantalum; Co40Fe40B20-Ta-Ni81Fe19-Ir20Mn80; high sensitivity soft-pinned layers; large area MTJ; linear magnetic tunnel junctions; linear response; magnetic fields; patterned MTJ; soft-pinned sensing layer; soft-pinning field; temperature 293 K to 298 K; thin films; Annealing; Magnetic sensors; Magnetic tunneling; Perpendicular magnetic anisotropy; Tunneling magnetoresistance; 1/f noise; Linear magnetic tunnel junctions; magnetoresistive sensors;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2012.2200468
