Imaging Magnetic Domain Structure of a High Entropy Alloy: Effect of Applied Magnetic Field

High-Entropy Alloys (HEAs) are recently introduced materials consisting of numerous-at least five-elements in nearly equal-atomic concentrations. Studying them, previously unexplored phase fields in multidimensional phase diagrams are now being explored. The HEA concept is based on a thermodynamic balance between mixing entropy and enthalpy, which defines values of several critical parameters that determine the formation of simple or complicated phases. Physical properties, like magnetism, are of great interest for these materials, even though they have not been extensively analyzed so far. Particularly, the exploration of the magnetic domain structure and its correlation with the micro- and nano-structural features of the materials is of high scientific value. In this work, we study the influence of the magnetic history on the alteration of the magnetic domain patterns in polycrystalline FeCoNiAl
0.9
Mn
0.9
High Entropy Alloy (HEA). For the study, we introduce a combinatorial method of Electron Backscatter Diffraction and Magnetic Force Microscopy imaging, which reveals specific magnetic domain structures in the grains of different crystallographic orientations. It is found that in the HEA polycrystal, an increase of the applied magnetic field affects the formation of magnetic domains and leads to a transition from a labyrinth-like pattern to a dotted domain configuration, which is expressed differently in the differently oriented grains.