Spin-transfer in nanopillars with a perpendicularly magnetized spin polarizer

J. M L Beaujoura, D. B. Bedaua, H. Liua, M. R. Rogosky, A. D. Kenta

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    Spin-transfer devices that incorporate a polarizer with its magnetization orthogonal to a switchable (free) layer offer the potential for ultra-fast switching, low power consumption and reliable operation. The non-collinear magnetizations lead to large initial spin-transfer torques, eliminating the incubation delay seen in devices with collinear magnetization. Here we present the basic electrical and magnetic characteristics of spin-valve nanopillars that incorporate a perpendicularly magnetized polarizer and demonstrate current-induced switching with short current pulses, down to 100 ps in duration. We have fabricated devices that have a CoNi polarizer with perpendicular magnetization and an in-plane magnetized 3 nm thick Co free layer and a 12 nm thick Co reference layer, each separated by thin (̃ 10 nm) Cu layers. The magnetization of the reference layer is collinear with that of free layer to read out the device state. The reference layer also contributes to the spin-accumulation acting on the free layer and leads to a spin-torque that favors the parallel (P) or antiparallel (AP) state depending on the current pulse polarity, reducing the requirement of precise pulse timing in precessional reversal. The anisotropy field of the perpendicular polarizer is 1.3 T, i.e. it is high enough so that in-plane fields (< 0.3 T) applied to switch the magnetizations of the reference and free layers do not reorient the polarizer. Our typical nanopillar device lateral dimensions are between 60 nm and 300 nm and nanopillars are positioned on coplanar waveguides to allow for broadband electrical connections and studies with fast rise time pulses, generated by an arbitrary waveform generator. The switching probability has been determined for variable pulse amplitude and duration, from 0.1 to 10 ns at room temperature.

    Original languageEnglish (US)
    Title of host publicationSpintronics II
    Volume7398
    DOIs
    StatePublished - 2009
    EventSpintronics II - San Diego, CA, United States
    Duration: Aug 2 2009Aug 5 2009

    Other

    OtherSpintronics II
    CountryUnited States
    CitySan Diego, CA
    Period8/2/098/5/09

    Fingerprint

    polarizers
    Magnetization
    magnetization
    Torque
    Collinear
    pulses
    Perpendicular
    torque
    Coplanar waveguides
    Induced currents
    Antiparallel
    Coplanar
    Anisotropy
    Electric power utilization
    Switches
    Polarity
    pulse amplitude
    Reversal
    Waveform
    Broadband

    Keywords

    • Magnetic random access memory
    • Orthogonal spin transfer MRAM
    • OST-MRAM
    • Perpendicular magnetization
    • Spin transfer

    ASJC Scopus subject areas

    • Computer Science Applications
    • Electrical and Electronic Engineering
    • Electronic, Optical and Magnetic Materials
    • Applied Mathematics
    • Condensed Matter Physics

    Cite this

    Beaujoura, J. M. L., Bedaua, D. B., Liua, H., Rogosky, M. R., & Kenta, A. D. (2009). Spin-transfer in nanopillars with a perpendicularly magnetized spin polarizer. In Spintronics II (Vol. 7398). [73980D] https://doi.org/10.1117/12.829018

    Spin-transfer in nanopillars with a perpendicularly magnetized spin polarizer. / Beaujoura, J. M L; Bedaua, D. B.; Liua, H.; Rogosky, M. R.; Kenta, A. D.

    Spintronics II. Vol. 7398 2009. 73980D.

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Beaujoura, JML, Bedaua, DB, Liua, H, Rogosky, MR & Kenta, AD 2009, Spin-transfer in nanopillars with a perpendicularly magnetized spin polarizer. in Spintronics II. vol. 7398, 73980D, Spintronics II, San Diego, CA, United States, 8/2/09. https://doi.org/10.1117/12.829018
    Beaujoura JML, Bedaua DB, Liua H, Rogosky MR, Kenta AD. Spin-transfer in nanopillars with a perpendicularly magnetized spin polarizer. In Spintronics II. Vol. 7398. 2009. 73980D https://doi.org/10.1117/12.829018
    Beaujoura, J. M L ; Bedaua, D. B. ; Liua, H. ; Rogosky, M. R. ; Kenta, A. D. / Spin-transfer in nanopillars with a perpendicularly magnetized spin polarizer. Spintronics II. Vol. 7398 2009.
    @inproceedings{6ab725cb4116402c986a2dbb3cbdc3b1,
    title = "Spin-transfer in nanopillars with a perpendicularly magnetized spin polarizer",
    abstract = "Spin-transfer devices that incorporate a polarizer with its magnetization orthogonal to a switchable (free) layer offer the potential for ultra-fast switching, low power consumption and reliable operation. The non-collinear magnetizations lead to large initial spin-transfer torques, eliminating the incubation delay seen in devices with collinear magnetization. Here we present the basic electrical and magnetic characteristics of spin-valve nanopillars that incorporate a perpendicularly magnetized polarizer and demonstrate current-induced switching with short current pulses, down to 100 ps in duration. We have fabricated devices that have a CoNi polarizer with perpendicular magnetization and an in-plane magnetized 3 nm thick Co free layer and a 12 nm thick Co reference layer, each separated by thin (̃ 10 nm) Cu layers. The magnetization of the reference layer is collinear with that of free layer to read out the device state. The reference layer also contributes to the spin-accumulation acting on the free layer and leads to a spin-torque that favors the parallel (P) or antiparallel (AP) state depending on the current pulse polarity, reducing the requirement of precise pulse timing in precessional reversal. The anisotropy field of the perpendicular polarizer is 1.3 T, i.e. it is high enough so that in-plane fields (< 0.3 T) applied to switch the magnetizations of the reference and free layers do not reorient the polarizer. Our typical nanopillar device lateral dimensions are between 60 nm and 300 nm and nanopillars are positioned on coplanar waveguides to allow for broadband electrical connections and studies with fast rise time pulses, generated by an arbitrary waveform generator. The switching probability has been determined for variable pulse amplitude and duration, from 0.1 to 10 ns at room temperature.",
    keywords = "Magnetic random access memory, Orthogonal spin transfer MRAM, OST-MRAM, Perpendicular magnetization, Spin transfer",
    author = "Beaujoura, {J. M L} and Bedaua, {D. B.} and H. Liua and Rogosky, {M. R.} and Kenta, {A. D.}",
    year = "2009",
    doi = "10.1117/12.829018",
    language = "English (US)",
    isbn = "9780819476883",
    volume = "7398",
    booktitle = "Spintronics II",

    }

    TY - GEN

    T1 - Spin-transfer in nanopillars with a perpendicularly magnetized spin polarizer

    AU - Beaujoura, J. M L

    AU - Bedaua, D. B.

    AU - Liua, H.

    AU - Rogosky, M. R.

    AU - Kenta, A. D.

    PY - 2009

    Y1 - 2009

    N2 - Spin-transfer devices that incorporate a polarizer with its magnetization orthogonal to a switchable (free) layer offer the potential for ultra-fast switching, low power consumption and reliable operation. The non-collinear magnetizations lead to large initial spin-transfer torques, eliminating the incubation delay seen in devices with collinear magnetization. Here we present the basic electrical and magnetic characteristics of spin-valve nanopillars that incorporate a perpendicularly magnetized polarizer and demonstrate current-induced switching with short current pulses, down to 100 ps in duration. We have fabricated devices that have a CoNi polarizer with perpendicular magnetization and an in-plane magnetized 3 nm thick Co free layer and a 12 nm thick Co reference layer, each separated by thin (̃ 10 nm) Cu layers. The magnetization of the reference layer is collinear with that of free layer to read out the device state. The reference layer also contributes to the spin-accumulation acting on the free layer and leads to a spin-torque that favors the parallel (P) or antiparallel (AP) state depending on the current pulse polarity, reducing the requirement of precise pulse timing in precessional reversal. The anisotropy field of the perpendicular polarizer is 1.3 T, i.e. it is high enough so that in-plane fields (< 0.3 T) applied to switch the magnetizations of the reference and free layers do not reorient the polarizer. Our typical nanopillar device lateral dimensions are between 60 nm and 300 nm and nanopillars are positioned on coplanar waveguides to allow for broadband electrical connections and studies with fast rise time pulses, generated by an arbitrary waveform generator. The switching probability has been determined for variable pulse amplitude and duration, from 0.1 to 10 ns at room temperature.

    AB - Spin-transfer devices that incorporate a polarizer with its magnetization orthogonal to a switchable (free) layer offer the potential for ultra-fast switching, low power consumption and reliable operation. The non-collinear magnetizations lead to large initial spin-transfer torques, eliminating the incubation delay seen in devices with collinear magnetization. Here we present the basic electrical and magnetic characteristics of spin-valve nanopillars that incorporate a perpendicularly magnetized polarizer and demonstrate current-induced switching with short current pulses, down to 100 ps in duration. We have fabricated devices that have a CoNi polarizer with perpendicular magnetization and an in-plane magnetized 3 nm thick Co free layer and a 12 nm thick Co reference layer, each separated by thin (̃ 10 nm) Cu layers. The magnetization of the reference layer is collinear with that of free layer to read out the device state. The reference layer also contributes to the spin-accumulation acting on the free layer and leads to a spin-torque that favors the parallel (P) or antiparallel (AP) state depending on the current pulse polarity, reducing the requirement of precise pulse timing in precessional reversal. The anisotropy field of the perpendicular polarizer is 1.3 T, i.e. it is high enough so that in-plane fields (< 0.3 T) applied to switch the magnetizations of the reference and free layers do not reorient the polarizer. Our typical nanopillar device lateral dimensions are between 60 nm and 300 nm and nanopillars are positioned on coplanar waveguides to allow for broadband electrical connections and studies with fast rise time pulses, generated by an arbitrary waveform generator. The switching probability has been determined for variable pulse amplitude and duration, from 0.1 to 10 ns at room temperature.

    KW - Magnetic random access memory

    KW - Orthogonal spin transfer MRAM

    KW - OST-MRAM

    KW - Perpendicular magnetization

    KW - Spin transfer

    UR - http://www.scopus.com/inward/record.url?scp=70449657664&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=70449657664&partnerID=8YFLogxK

    U2 - 10.1117/12.829018

    DO - 10.1117/12.829018

    M3 - Conference contribution

    SN - 9780819476883

    VL - 7398

    BT - Spintronics II

    ER -