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Module: FM|NM Interface

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FM||NM module models the interface between a ferromagnet and a non-magnet, capturing the spin-torque on the magnet at the interface.

Model Description

The FM|NM module is modeled with a series and shunt conductances as shown below:

Where the shunt is on the "NM" side and the spin current flowing through it is the spin-torque, which can be provided to an LLG module.

Parameters

Parameter Symbol Units
Conductance gif.latex?G_0 gif.latex?\Omega^{-1}
Polarization gif.latex?P -
Slonczewski like torque coeff. gif.latex?a -
FIeld like torque coeff. gif.latex?b -

Model Conductance Matrices

Magnet Rotation

The matrices above are for magnet in +z direction. To obtain conductances matrices for a magnet is any general direction "m",we need to basis transformation these matrix,  the transformation matrix being obtained by Rodrigues formula. The rotation matrix is given as:

where, gif.latex?theta and gif.latex?phi are equatorial and azimuthal angles referenced from the gif.latex?+hat z direction. This information is provided to the module using the third terminal "m".

The matrices can then be rotated using the transformation formula:

gif.latex?G(hat m)=U_R^dagger G(hat z

Download

The module, as a part of the library, can be downloaded here.

References

  • A. Brataas, G. E. W. Bauer, and P. J. Kelly, “Non-collinear magnetoelectronics,” Phys. Rep., vol. 427, no. 4, pp. 157–255, Apr. 2006
  • S. Srinivasan, V. Diep, B. Behin-Aein, A. Sarkar, and S. Datta, “Modeling Multi-Magnet Networks Interacting Via Spin Currents,” ArXiv13040742 Cond-Mat, Apr. 2013