Hi I chose a Monte Carlo simulation of the 2D Ising model as my Computational Physics course project. Unfortunately, I ran intro problems when formulating the exact problem since my professor probably wants me to simulate a real life material and extract magnetization curve M(T,H) out of it. After doing some superficial research on the topic it has occurred to me that 2D Ising model presented in most MC textbooks is just a toy model/framework that is extended and/or modified according to needs. Physical quantities parametrizing simulations in most examples are just dimensionless ratios.. Problem probably still remains when to introduce naively a third dimension (making lattice primitive cubic). Implementing a fcc/bcc type of lattice in 3D seems quite nontrivial (a custom underlying data structure is needed, plain arrays won't suffice). Is there any materials whose magnetic properties can be described by 2D/3D Ising model? What about Heisenberg model? To put things in perspective, 30-50h of programming is expected.