Tunneling-Magnetoresistance Ratio Comparison of MgO-Based Perpendicular-Magnetic-Tunneling-Junction Spin Valve Between Top and Bottom Co2Fe6B2 Free Layer Structure.
For the perpendicular-magnetic-tunneling-junction (p-MTJ) spin valve with a nanoscale-thick bottom Co2Fe6B2 free layer ex situ annealed at 400 °C, which has been used as a common p-MTJ structure, the Pt atoms of the Pt buffer layer diffused into the MgO tunneling barrier. This transformed the MgO tunneling barrier from a body-centered cubic (b.c.c) crystallized layer into a mixture of b.c.c, face-centered cubic, and amorphous layers and rapidly decreased the tunneling-magnetoresistance (TMR) ratio. The p-MTJ spin valve with a nanoscale-thick top Co2Fe6B2 free layer could prevent the Pt atoms diffusing into the MgO tunneling barrier during ex situ annealing at 400 °C because of non-necessity of a Pt buffer layer, demonstrating the TMR ratio of ~143 %.
Department of Electronics and Computer Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
Du-Yeong
DY
Lee
Department of Electronics and Computer Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
Seung-Eun
SE
Lee
Department of Electronics and Computer Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
Tae-Hun
TH
Shim
Department of Electronics and Computer Engineering, Hanyang University, Seoul, 04763, Republic of Korea. parkjgL@hanyang.ac.kr.
Jea-Gun
JG
Park
BEOL; Pt diffusion; TMR ratio; Top and bottom free layer; p-MTJ
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