A Data-Driven Extended Landau Theory Method for the Coercivity Analysis of Magnetic Materials

The Ginzburg-Landau theory was used to analyze the mechanism that determines magnetic properties from information on the magnetic domain structure of magnetic materials. The Ginzburg-Landau theory enables the analysis of free energy landscape using magnetization as an order parameter. In this study, we extend the Ginzburg-Landau theory to directly link magnetic properties and magnetic domain structure by incorporating data science into the theoretical framework. This enables a data-driven analysis of the coercivity mechanism. The features extracted from the magnetic domain structure were used as new order parameters to connect the data space with the original physical space. Magnetic properties were then derived from the free energy landscape visualized in data space. As a result, we proposed a method in which variables and formulas in the data space are easily interpretable as physical quantities and the theory can be easily generalized.