Magnetic simulation

i want to make a lammps code that simulates a dipole based magnetic field but don’t know where to start.
can anyone give me an example code or article?

Your description of your project is far too vague and unspecific to give any meaningful specific advice, let alone quote examples.

As for finding suitable literature, I suggest you discuss with people that are familiar with your research and then use the information given to search the literature. Please keep in mind that you usually first need to identify possible models and strategies and only then look for a suitable simulation software.

i’'m wanting to simulate the magnetic bond of Fe3O4 according to the article about magnetic fluid


This is still rather vague. What article are you speaking about?
If your goal is to simulation the magneto-elastic properties of Fe3O4, I encourage you to have a look at the SPIN package. I know some groups have been starting some studies leveraging it.