Spinsim GSL

Macrospin Magnetic Simulator
Center for Magnetic Recording Research
University of California, San Diego

Email Contact: ivanv at yulaev dot com
About Spinsim GSL
Spinsim GSL is a macromagnetic simulator of multi-layered nano-magnetic thin film structures. It is geared towards simulation of the behavior of thin film magnetization under stimulus from perpendicularly-applied currents and fields. It is particularly suited for simulation of magnetization dynamics due to spin torque transfer, as modeled by the Landau Lifshitz Gilbert equations with the Slonczewski Spin Torque Transfer term. One or two free magnetic layers, plus an optional fixed layer, can be included in a simulation model; inter-layer interaction in the form of mutual demagnetizing field and exchange coupling can be simulated. A GUI is provided for setting up all of the relevant parameters for the model. Plotting of results is supported.

Features of the Spinsim GSL macrospin simulator include:
  • Simulation of multi-layer structures. Each layer is modeled as a single magnetic "spin".
  • Calculation of self and mutual dipole (demagnetizing) fields
  • Calculation of magnetostatic behavior based on applied magnetic field
  • Calculation of dynamic behavior based on spin torque transfer, arising from applied current; functions for both metallic junctions and tunnel junctions are provided
  • Exchange coupling between layers
  • Generation of phase plots (two dimensional color map), hysteresis loops (J and H), and single-point time-domain simulations
  • Allows for application of both time-independent and time-dependent applied fields and currents
  • FMR Simulations
  • Support for CGS and SI units
  • Ability to derive damping from simulation results

Phase Plot Example

The latest release of Spinsim GSL can be found here.

Spinsim GSL Revision History
  • 2011-04-19 - Fixed Typo in plotting function for generating Mz vs J hysteresis loop
  • 2011-03-29 - Initial Release Published on this site

The user manual is provide with the release. The Spinsim GSL User Manual is also available separately; aside from containing setup and usage instructions, it gives a much more thorough description of the software's function and the macrospin model used.

For new users, a tutorial is available and is recommended as a starting point for learning to use Spinsim GSL. This tutorial describes setting up the Spinsim GSL simulator, and then shows how to run several different simple simulations of commonly-used magnetic structures.

The Spinsim GSL User Manual provides an extensive list of references that are helpful for understanding how a macrospin approximation works, as well as giving general knowledge about the subject of nanoscale magnetics. Selected references that are particularly relevant and instructive are reproduced below:

Spinsim GSL is distributed under the GNU General Public License License. The program is property of the CMRR at the University of California, San Diego. A full text of the license may be found at http://www.gnu.org/copyleft/gpl.html.

No warrantee of fitness or performance is expressed or implied. Use at your own risk.

Spinsim GSL would not be possible without the help of
  • Marko Lubarda, under Prof. Fullerton & Prof. Lomakin. His input was useful for bettering the accuracy of simulations.
  • Christel Berthelot and Stephane Mangin (Nancy). This team has done extensive work in Macrospin simulations, and early revisions of the code borrowed heavily from their approach.
  • Stephanie Moyerman, for writing the early revisions of the code and giving advising comments throughout the development.

Spinsim GSL was primarily developed by Ivan Yulaev, while working as an undergraduate research assistant at the Center for Magnetic Recording Research under Professor Eric Fullerton. He can be reached by email at ivan_yulaev at yahoo.com.