Kerr effect microscope combined with a pulse magnet to observe high-entropy alloys fabricated using combinatorial technology

Abstract

We developed a module-type two-dimensional (2D) polar Kerr effect microscope using a pulse magnet with a pulse width of 13 ms and a maximum magnetic field of 7 kOe to accelerate the development of new soft magnetic materials. We also developed an algorithm and method to extract still images from a measurement movie file when the pulse magnetic field is applied. To evaluate the performance of this instrument, we measured high-entropy alloys based on FeCoMn samples, which were screened and selected using material informatics. Samples obtained through depositing Pt, Zn, Cu, and Ru on high-entropy FeCoMn alloys exhibited a brightness distribution proportional to the Kerr rotation angle in the applied magnetic field. The developed instrument enabled the high-speed magnetic field mapping of composition-spread thin films and is expected to accelerate new material development.