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

Volume

48

Issue

11

fYear

2012

Firstpage

3719

Lastpage

3722

Abstract

Large area MTJs with linear response and very larger sensitivities are needed to fulfill the requirements for the detection of pT/Hz^0.5 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;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2012.2200468

Filename

6332696