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Mario Gutierrez

Electric current without magnetoresistance effect

Dear, is it possible not to consider the effects of magnetoresistance in mage?

Should I consider bj0 = bj1 = bj2 = 0 and R_p = R_AP = 0?

thanks

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    Jakub Chęciński

    The magnetoresistance module does not affect the system dynamics, it only provides a convenient way to translate the magnetization output into a resistance output. If you do not want this output, you can simply not specify the module and it will not appear in the mif file.

    On the other hand, if you are interested in disabling magnetoresistance effects on the dynamics (i.e. a constant current density in the whole layer), you can do that by setting R_p = R_AP in the current excitation window. Do not set it to zero though, it's better to use a dummy value such as e.g. 100.

    Setting bj0 = bj1 = bj2 = 0 will not change magnetoresistance, but it will disable the out-of-plane (field-like) torque in STT.

    Kind regards,

    Jakub

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      Anonymous

      When the direction of the electric current is introduced to the free layer, the direction is indicated by the zheight scalar function.

      I have a question about completing the excitation details tab for current (mA)

      For the MTJ example

      scalar field 1

      zheight = bottom height of the separator, for the example it should be 0.7 nm.


      scalar field 2

      zheight = bottom height of the free layer, for the example it should be 0.7nm + 1.4 nm

      This indicates that a current enters perpendicular to the free layer or not, 
      for simplicity the fixed layer does not exist ?

      I would be very grateful if you could resolve that doubt.

      Thank you

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    Anonymous

    When the direction of the electric current is introduced to the free layer, the direction is indicated by the zheight scalar function.

    I have a question about completing the excitation details tab for current (mA)

    For the MTJ example

    scalar field 1

    zheight = bottom height of the separator, for the example it should be 0.7 nm.


    scalar field 2

    zheight = bottom height of the free layer, for the example it should be 0.7nm + 1.4 nm

    This indicates that a current enters perpendicular to the free layer or not, 
    for simplicity the fixed layer does not exist ?

    I would be very grateful if you could resolve that doubt.

    Thank you

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      Anonymous

      Your example looks correct to me. The current will flow into the free layer perpendicularly, but its spin polarization will be determined by the fixed layer magnetization.

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        Mario Gutierrez

        ok, but when you perform spin wave analytical calculations, usually the fixed layer is not considered. Can polarization of spins of the current be arbitrarily entered?

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        Anonymous

        As far as I know, it is not possible in the MF_CurrentFlowEvolver (note: I'm not the author of MF_CurrentFlowEvolver code). It may be possible in the other current evolver available ( SpinXferEvolve ), which can be specified manually in the evolver window. From what I see in the OOMMF manual, SpinXfer allows you to specify polarization as an arbitrary fixed vector. I have never tested it myself, though.

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        Jakub Chęciński

        Please refer to the manual page if you wish to try it:

        https://math.nist.gov/oommf/doc/userguide12a5/userguide/Standard_Oxs_Ext_Child_Clas.html#SX

        You can set the necessary parameters in MAGE by selecting Miscellaneous -> SpinXferEvolve -> Advanced. Unfortunately, in the current version it is not possible to specify the current profile from the Excitations window if you are using the SpinXferEvolver.

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    Mario Gutierrez

    when run the code in OOMMF, the program it asks me to enter the vrange, in my case i put constant pulse of current, this shoud be any vector constant or not?

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      Anonymous

      If you want a constant current amplitude, you can use "Fixed" option in the current specification window. Using vrange directly is more complicated, but if you want to do that, enter the same value as starting and stopping point (e.g. { 1.0 1.0 0 } for constant current with amplitude 1.0)

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        Mario Gutierrez

        for only current I must indicate current_mode 1.0?

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