The 81st JSAP Autumn Meeting, 2020

Presentation information

Oral presentation

10 Spintronics and Magnetics » 10.3 Spin devices, magnetic memories and storages

[10p-Z08-11~17] 10.3 Spin devices, magnetic memories and storages

Thu. Sep 10, 2020 4:00 PM - 6:00 PM Z08

Satoshi Iihama(Tohoku Univ.)

5:45 PM - 6:00 PM

[10p-Z08-17] Tunnel magnetoresistance sensor devices with amorphous CoFeBTa-based free layers

〇(P)Mahmoud Rasly Eldesouky1, Tomoya Nakatani1, Jiangnan Li1, Hossein Sepehri-Amin1, Hiroaki Sukegawa1, Yuya Sakuraba1 (1.NIMS)

Keywords:Magnetic field sensor, tunnel magnetoresistance, 1/f noise

To improve the magnetic field sensing performance of CoFeB/MgO/CoFeB magnetic tunnel junction (MTJ) sensor devices, the CoFeB free layer (FL) is often laminated with soft-magnetic materials such as NiFe. However, the lamination of NiFe above/below CoFeB tends to degrade the TMR ratio because the 111 texture of NiFe propagates to the CoFeB layer. In this study, we introduced an amorphous (Co0.4Fe0.4B0.2)91Ta9 in the FL of top-pinned spin-valve MTJs, resulting in no influnce on the texture of CoFeB and thereby TMR ratios. Linear R-H curves with a negligible coercivity have been obtained by using two-step annealing technique. The low-frequency properties have been investigated. All sensors showed 1/f noise behaviors. Moreover, we achieved a detectivity as low as ~ 2 nT/Hz0.5 using a single MTJ sensor and ~ 600 pT/Hz0.5 using a Wheatstone bridge sensor.