[2Bp01-10] Surface Analysis/Applied Surface Science/Evaluation Technique (ASS)

[2Bp08] Origin of magnetic moment increase in (Fe₇₅Co₂₅)_100-x-Ir_x studied by magnetic circular dichroism (MCD)

*Takahiro Kawasaki¹, Takahiro Yamazaki¹, Alexandre Lira Foggiatto¹, Kentaro Fuku¹, Ryo Toyama², Varun Kumar Kushwaha², Yuya Sakuraba², Yuma Iwasaki², Yoshinori Kotani³, Takuo Ohkochi³, Kotaro Higashi³, Naomi Kawamura³, Masato Kotsugi¹ (1. Graduate School of Advanced Engineering, Tokyo University of Science, 2. National Institute for Materials Science (NIMS), 3. Japan Synchrotron Radiation Research Institute (JASRI))

Ferromagnetic materials are vital for applications like electric vehicle motors and magnetic memory. Fe₇₅Co₂₅, positioned atop the Slater-Pauling curve, displays strong magnetism. Advances in Materials Informatics accelerate magnetic property enhancement beyond traditional methods. Prior research combined calculations and machine learning to predict (Fe₇₅Co₂₅)_97.5-Ir_2.5's superior magnetism. Experimentally, it surpassed the Slater-Pauling curve, with improved magnetic resistance. However, understanding the complex multi-element magnetic alloys' mechanism remains elusive. To address this, Magnetic Circular Dichroism (MCD) was employed, revealing the origin of FeCoIr magnetic moment via element-selective analysis. Soft and hard X-ray MCD measurements were carried out at SPring-8. The study clarifies how Ir addition boosts spin and orbital magnetic moments across elements, bridging theory and experimentation.