These micromagnetic simulations are done in MATLAB. Each rotating vector represents an individual nanoparticle under the macrospin approximation. These simulations attempt to see if treating individual particles in a collection as spins in a typical micromagnetic discretization scheme yields realistic results. Time-domain measurements of these types of dynamics is the focus of my dissertation work at the University of South Carolina.  This work is an extension of a previous work of Ru Zhu.  It extends the former by adapting it to CPUs (rather than GPUs), going to a 3-D model space, animating the simulation, and various other changes including plotted outputs not shown in the video.

Download the MATLAB Micromagnetic Animation Code Here:

Slideshow of my research on inductive time-domain measurements of magnetization dynamics of dense collections of magnetic nanoparticles

In this micromagnetic simulation each vector represents the average of all local atomic magnetic moments over the surrounding  volume.  Here a cubic magnetic nanoparticle is modeled under a dynamical external field to see how the internal magnetization vectors change directions.  As the cube gets larger the exchange effect, being a short-range interaction, falls off and the dipolar field becomes dominant.  This leads to the moments to begin to diverge and leads to complex buckling of the coherent structure.  Spin waves are set up as the exchange interaction takes longer to transmit across the volume, leading to phase differences.

Link to my paper on inductive time-domain measurements of magnetization dynamics of dense collections of magnetic nanoparticles

Nanoparticle Chain Simulator

Videos of some simulations using the Nanoparticle Chain Simulator

My research paper on the computer simulated frequency response of interacting magnetic nanoparticles in dynamic magnetic fields

Important: Save this file as "LL.m" to your working directory

Important: Save this file as "dMdt.m" to your working directory

Important: Save this file as "LL.fig" to your working directory

The chain simulator looks at the effect of dipolar interactions of chains of interacting spins.  These downloads are the 3 MATLAB files needed to run the Magnetic Nanoparticle Simulator.  Paste each of the first 2 into their own new M-file and save the Simulator as "LL.m" and the second one as "dMdt.m".  Save the 3rd file as "LL.fig" to the same folder.  To run the simulator type "LL" in the MATLAB command window.  If these 3 files are saved in the current directory, the GUI will open and allow you to configure the simulation parameters.  Then click the "Run Simulation" button.  

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MATLAB Micromagnetics