Highly Enhanced TMR Ratio and Δ for Double MgO-based p-MTJ Spin-Valves with Top Co2Fe6B2 Free Layer by Nanoscale-thick Iron Diffusion-barrier

Seung-Eun Lee; Jong-Ung Baek; Jea-Gun Park

doi:10.1038/s41598-017-10967-x

Highly Enhanced TMR Ratio and Δ for Double MgO-based p-MTJ Spin-Valves with Top Co₂Fe₆B₂ Free Layer by Nanoscale-thick Iron Diffusion-barrier

Sci Rep. 2017 Sep 19;7(1):11907. doi: 10.1038/s41598-017-10967-x.

Authors

Seung-Eun Lee¹, Jong-Ung Baek², Jea-Gun Park³

Affiliations

¹ MRAM Center, Department of Electronics and Computer Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
² MRAM Center Department of Nanoscale Semiconductor Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
³ MRAM Center, Department of Electronics and Computer Engineering, Hanyang University, Seoul, 04763, Republic of Korea. parkjgl@hanyang.ac.kr.

Abstract

For double MgO-based p-MTJ spin-valves with a top Co₂Fe₆B₂ free layer ex-situ annealed at 400 °C, the insertion of a nanoscale-thickness Fe diffusion barrier between the tungsten (W) capping layer and MgO capping layer improved the face-centered-cubic (f.c.c.) crystallinity of both the MgO capping layer and tunneling barrier by dramatically reducing diffusion of W atoms from the W capping layer into the MgO capping layer and tunneling barrier, thereby enhancing the TMR ratio and thermal stability (Δ). In particular, the TMR ratio was extremely sensitive to the thickness of the Fe barrier; it peaked (154%) at about 0.3 nm (the thickness of only two atomic Fe layers). The effect of the diffusion barrier originated from interface strain.

Publication types

Research Support, Non-U.S. Gov't