Dependence of spin-transfer switching current on free layer thickness in Co–Fe–B∕MgO∕Co–Fe–B magnetic tunnel junctions

2006 ◽  
Vol 89 (3) ◽  
pp. 032505 ◽  
Author(s):  
Hitoshi Kubota ◽  
Akio Fukushima ◽  
Yuichi Ootani ◽  
Shinji Yuasa ◽  
Koji Ando ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Spin Transfer ◽  
Free Layer ◽  
Switching Current

Magnetization Reversal by Spin-Polarized Current in Magnetic Tunnel Junctions with MgO Barriers

2006 ◽  
Vol 45 ◽  
pp. 2633-2639
Author(s):  
Hitoshi Kubota ◽  
A. Fukushima ◽  
Y. Ootani ◽  
S. Yuasa ◽  
K. Ando ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Layer Thickness ◽  
Magnetization Reversal ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Magnetic Tunnel Junction ◽  
Free Layer ◽  
Switching Model ◽  
Switching Current ◽  
Experimental Values

Co-Fe-B/MgO/Co-Fe-B magnetic tunnel junctions were fabricated using UHV magnetron sputtering. Magnetoresistance and spin-transfer switching properties were investigated as a function of Co-Fe-B free layer thickness, between 1.5 nm and 3 nm. The intrinsic switching current and the thermal stability were derived from the pulse duration dependence of the switching current, analyzed based on the thermally activated switching model. Both switching currents, corresponding to parallel (P) to antiparallel (AP) (Ic0 +) and AP to P (Ic0 –) magnetization reversal, were found to be roughly proportional to the free layer thickness. The averaged intrinsic switching current density Jc0 av = (Ic0 +–Ic0 –)/(2A) (where A is the cell area) was in the range of 1–2×107 A/cm2. The experimental values of Jc0 ± agreed with theoretical values, determined taking into account the spintransfer efficiency for the case of magnetic tunnel junction. The thermal stability of the P and AP states was different, but roughly proportional to the free layer thickness in both cases. We attribute this difference to a disparity in the net magnetic field acting on the free layer magnetization in the P and AP states. The average of the thermal stability in the two states varied from 30 to 60 when the free layer thickness was increased. According to our findings, to guarantee the non-volatility of an MRAM device for about 10 years, the Co-Fe-B free layer should be thicker than 2 nm.

Reducing spin-torque switching current by incorporating an ultra-thin Ta layer with CoFeB free layer in magnetic tunnel junctions

2014 ◽  
Vol 105 (24) ◽  
pp. 242411 ◽  
Author(s):  
R. S. Liu ◽  
H. Meng ◽  
V. B. Naik ◽  
C. H. Sim ◽  
S. Yap ◽  
...  
Keyword(s):  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Spin Torque ◽  
Free Layer ◽  
Switching Current

Effect of free layer thickness and shape anisotropy on the transfer curves of MgO magnetic tunnel junctions

2008 ◽  
Vol 103 (7) ◽  
pp. 07A910 ◽  
Author(s):  
P. Wiśniowski ◽  
J. M. Almeida ◽  
S. Cardoso ◽  
N. P. Barradas ◽  
P. P. Freitas
Keyword(s):  
Layer Thickness ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Shape Anisotropy ◽  
Free Layer

scholarly journals Spin-transfer switching in magnetic tunnel junctions with synthetic ferri-magnetic free layer

2010 ◽  
Vol 200 (5) ◽  
pp. 052018 ◽  
Author(s):  
M Nishimura ◽  
M Oogane ◽  
H Naganuma ◽  
N Inami ◽  
S Ikeda ◽  
...  
Keyword(s):  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Spin Transfer ◽  
Free Layer

Reduction of switching current density in perpendicular magnetic tunnel junctions by tuning the anisotropy of the CoFeB free layer

2012 ◽  
Vol 111 (7) ◽  
pp. 07C907 ◽  
Author(s):  
M. T. Rahman ◽  
A. Lyle ◽  
P. Khalili Amiri ◽  
J. Harms ◽  
B. Glass ◽  
...  
Keyword(s):  
Current Density ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Free Layer ◽  
Switching Current

Reduction in switching current using a low-saturation magnetization Co–Fe–(Cr, V)–B free layer in MgO-based magnetic tunnel junctions

2009 ◽  
Vol 105 (7) ◽  
pp. 07D117 ◽  
Author(s):  
Hitoshi Kubota ◽  
Akio Fukushima ◽  
Kay Yakushiji ◽  
Satoshi Yakata ◽  
Shinji Yuasa ◽  
...  
Keyword(s):  
Saturation Magnetization ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Free Layer ◽  
Switching Current
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