Magnetoresistance variation of magnetic tunnel junctions with NiFeSiB/CoFeB free layers depending on MgO tunnel barrier thickness

Ji Ung Cho, Do Kyun Kim, Tian Xing Wang, Shinji Isogami, Masakiyo Tsunoda, Migaku Takahashi, Young Keun Kim

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


We developed NiFeSiB/CoFeB hybrid free-layers for magnetic tunnel junctions (MTJs) with MgO tunnel barrier layers. These junctions show tunneling magnetoresistance (TMR) ratios and resistance-area (RA) values ranging from 118-209% and 36-2380 Ω μm2, respectively, obtained at room temperature. Compared to the CoFeB single free-layer case, the NiFeSiB/CoFeB hybrid free-layer approach has the advantage of lowering saturation magnetization. The low magnetization material would be effective to decrease the switching current in spin transfer torque (STT) switching. The experimental results show that the RA value depends not only on the thickness of the MgO barrier but also on the structure of the free layer used. Tunable in the TMR ratio and RA value using the design of the hybrid free-layer, our hybrid free-layered MTJs demonstrate a desirable lower RA value but a similar TMR ratio in comparison to the CoFeB free-layered ones.

Original languageEnglish
Pages (from-to)2547-2550
Number of pages4
JournalIEEE Transactions on Magnetics
Issue number11 PART 2
Publication statusPublished - 2008 Nov

Bibliographical note

Funding Information:
This work was supported by the Korea Science and Engineering Foundation through the National Research Lab Program (No. M10500000105-05J0000-10510), and Tera-level Nanode-vices Program (No. M103KC010006-06K0301-00631).


  • Hybrid free layer
  • Low saturation magnetization
  • Magnetic tunnel junction
  • NiFeSiB

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


Dive into the research topics of 'Magnetoresistance variation of magnetic tunnel junctions with NiFeSiB/CoFeB free layers depending on MgO tunnel barrier thickness'. Together they form a unique fingerprint.

Cite this