From a Thermodynamic Model to a Magnetic Hysteresis Model

The magnetic characteristics of magnetic materials are determined by various factors such as the type and arrangement of atoms comprising the microstructure, that is, the crystalline structure. This model uses a coarse-grained modeling approach to capture the relationship of this microscale phenomenon as it relates to the macroscale behavior of magnetic materials. One of the methods of coarse-grained modeling is defined according to state variables having no correlation with the history of the material such as temperature and pressure, taking into account thermodynamic state variables such as energy and entropy. However, the phenomenon of hysteresis that appears in magnetism is clearly dependent on the history of the material; therefore, there are various difficulties involved in this sort of thermodynamic approach. At the heart of the phenomenon of hysteresis exists a state variable called free energy, which can be described according to thermodynamics, but it is obfuscated by a phenomenon resembling macroscale friction. Therefore, here we introduce a model to describe the resulting historically dependent magnetic properties.