Novel design and fabrication of magnetic random access memory based on nano-ring-type magnetic tunnel junctions

X. F. Han, H. X. Wei, Z. L. Peng, H. D. Yang, J. F. Feng, G. X. Du, Z. B. Sun, L. X. Jiang, Q. H. Qin, M. Ma, Y. Wang, Z. C. Wen, D. P. Liu, W. S. Zhan

    Research output: Contribution to journalArticlepeer-review

    8 Citations (Scopus)


    Nano-ring-type magnetic tunnel junctions (NR-MTJs) with the layer structure of Ta(5)/Ir22Mn78(10) /Co75Fe25(2)/Ru(0.75) /Co60Fe20B20(3) /Al(0.6)-oxide/Co60Fe20B20(2.5)/ Ta(3)/Ru(5) (thickness unit: nm) were nano-fabricated on the Si(100)/SiO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography (EBL) and Ar ion-beam etching techniques. The smaller NR-MTJs with the inner- and outer-diameter of around 50 and 100 nm and also their corresponding NR-MTJ arrays were nano-patterned. The tunneling magnetoresistance (TMR&R) versus driving current (I) loops for a spin-polarized current switching were measured, and the TMR ratio of around 35% at room temperature were observed. The critical values of switching current for the free Co60Fe20B20 layer relative to the reference Co60Fe20B20 layer between parallel and anti-parallel magnetization states were between 0.50 and 0.75 mA in such NR-MTJs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbit/inch2 even 6 Gbite/inch2 are possible using both 1 NR-MTJ+1 transistor structure and current switching mechanism based on based on our fabricated 4 × 4 MRAM demo devices.

    Original languageEnglish
    Pages (from-to)304-306
    Number of pages3
    JournalJournal of Materials Science and Technology
    Issue number3
    Publication statusPublished - 2007 May


    • MRAM
    • NR-MTJ
    • Nano-ring-type magnetic tunnel junctions
    • Spin polarization
    • Spin transfer effect

    ASJC Scopus subject areas

    • Ceramics and Composites
    • Mechanics of Materials
    • Mechanical Engineering
    • Polymers and Plastics
    • Metals and Alloys
    • Materials Chemistry


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