Browse > Article
http://dx.doi.org/10.4283/JKMS.2005.15.6.315

Magnetoresistance Effects of Magnetic Tunnel Junctions with Amorphous CoFeSiB Single and Synthetic Antiferromagnet Free Layers  

Hwang, J.Y. (Dept. of Physics, Sookmyung Women's University)
Kim, S.S. (Dept. of Physics, Sookmyung Women's University)
Rhee, J.R. (Dept. of Physics, Sookmyung Women's University)
Publication Information
Journal of the Korean Magnetics Society / v.15, no.6, 2005 , pp. 315-319 More about this Journal
Abstract
To obtain low switching field ($H_{SW}$) we introduced amorphous ferromagnetic $Co_{70.5}Fe_{4,5}Si_{15}B_{10}$ single and synthetic antiferromagnet (SAF) free layers in magnetic tunnel junctions (MTJs). The switching characteristics for MTJs with structures $Si/SiO_2/Ta$ 45/Ru 9.5/IrMn 10/CoFe 7/AlOx/CoFeSiB 7 or CoFeSiB (t)/Ru 1.0/CoFeSiB (7-t)/Ru 60 (in nm) were investigated and compared to MTJs with $Co_{75}Fe_{25}$ and $Ni_{80}Fe_{20}$ free layers. CoFeSiB showed a lower saturation magnetization of $560 emu/cm^3$ and a higher anisotropy constant of $2800\;erg/cm^3$ than CoFe and NiFe, respectively. An exchange coupling energy ($J_{ex}$) of $-0.003erg/cm^2$ was observed by inserting a 1.0 nm Ru layer in between CoFeSiB layers. In the CoFeSiB single and SAF free layer MTJs, it was frond that the size dependence of the $H_{SW}$ originated from the lower $J_{ex}$ experimentally and by micromagnetic simulation based on the Landau-Lisfschitz-Gilbert equation. The CoFeSiB SAF structures showed lower $H_{SW}$ than that of NiFe, CoFe and CoFeSiB single structures. The CoFeSiB SAF structures were proved to be beneficial far the switching characteristics such as reducing the coercivity and increasing the sensitivity in micrometer to submicrometer-sized elements.
Keywords
magnetic tunnel junctions; tunneling magnetoresistance; switching field; synthetic antiferrornagnet; magnetization switching; CoFeSiB;
Citations & Related Records
연도 인용수 순위
  • Reference
1 E. C. Stoner and E. P. Wohlfarth, Phil. Trans. Roy. Soc. A 240, 599(1948)
2 A. Kaufler, Y. Luo, K. Samwer, G Gieres, M. Vieth, and J. Wecker, J. Appl. Phys. 91, 1701(2002)   DOI   ScienceOn
3 S. S. P. Parkin, C. Kaiser, A. Panchula, P. M. Rice, B. Hughes, M. Samant, and S-H. Yang, Nature Materials 3, 862(2004)   DOI   ScienceOn
4 N. Wiese, T. Dimopoulos, M. Ruhrig, J. Wecker, H. Bruckl, and G. Reiss. Appl. Phys. Lett. 85,2020(2004)   DOI   ScienceOn
5 D. Wang, C. Nordman, J. Daughton, Z. Qian, and J. Fink, IEEE Trans. Magn. 40, 2269(2004)   DOI   ScienceOn
6 N. Tezuka, N. Koike, T. Nozaki, K. Inomata, and S. Sugimoto, J. Appl. Phys. 93, 7441(2003)   DOI   ScienceOn
7 J. S. Moodera, L. R. Kinder, T. M. Wong, and R. Meservey, Phys. Rev. Lett. 74, 3273(1995)   DOI   ScienceOn
8 H. Kano, K. Bessho, Y. Higo, K. Ohba, M. Hashimoto, T. Mizuguchi, and M. Hosomi, The Digest of Intermag Europe 2002, Amsterdam, the Netherlands, BB04(2002)
9 M. S. Song, B. S. Chun, Y. K. Kim, I. J. Hwang, and T. W Kim, J. Appl. Phys. in press
10 B. S. Chun, I. S. Yoo, Y. K. Kim, J. Y. Hwang, J. R. Rhee, T. W Kim, and W. J. Park, Appl. Phys. Lett. 87, 082508(2005)   DOI   ScienceOn
11 H. Van den Berg, W. Clemens, G. Gieres, G. Rupp, W. Schelter, and M. Vieth, IEEE Trans. Magn. 32, 4624(1996)   DOI   ScienceOn
12 K. R. Coffey, B. A. Gurney, D. E. Hein, H. Lefakis, D. Mauri, V. S. Speriosu, and D. R. Wilhoit, US Patent 5583725(1996)
13 The LLG Micromagnetics $Simulator^tm$