J Rocha

Hi. I'm Julio, I'm from Brazil and I study computational physics. I've been working in magnetic materials at nanoscale. I was searching for a science forum in order to improve my knowledge in others fields, especially in English. In my point of view this will take place of the scientific periodic. So, I expect to learn and contribute to this forum in a very constructive way.

The exchange interaction comes up from the superposition of the electron wave functions in the crystal. These wave functions are solution of the Schrödinger's equation. For simplicity we can consider only the interaction betweens ions and electrons, i.e. just Coulomb interaction. Roughly, according to Pauli principle if the spatial wave functions are odd, the spins align in the same direction, so the material is ferromagnetic. If the spatial wave function are even, the spins align in opposite direction, so the material is anti-ferromagnetic. You can find the demonstration of the exchange interaction in this book: Introduction to the Theory of Ferromagnetism, Amikam Aharoni - Clarendon Press - Oxford 1998.

The exchange interaction is the solution of Schrödinger's equation for the Coulomb potential considering Pauli exclusion principle.