The Heisenberg model is a theoretical framework used in statistical mechanics and condensed matter physics to describe magnetic systems. It focuses on the interactions between spins, which are intrinsic angular momentum properties of particles like electrons. In this model, spins are represented as vectors that can point in different directions, and their interactions lead to various magnetic behaviors, such as ferromagnetism and antiferromagnetism. Named after physicist Werner Heisenberg, the model simplifies the complex interactions in a lattice of spins by assuming that each spin interacts only with its nearest neighbors. This approach allows researchers to study phase transitions and critical phenomena in magnetic materials, contributing to our understanding of magnetism in solids.