Yamasaki Y, Ishii Y, Sasabe N
Center for Basic Research on Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan.
International Center for Synchrotron Radiation Innovation Smart, Tohoku University, Sendai, Japan.
Sci Technol Adv Mater. 2025 Jun 18;26(1):2513217. doi: 10.1080/14686996.2025.2513217. eCollection 2025.
X-ray magnetic circular dichroism (XMCD) and X-ray magnetic linear dichroism (XMLD) are powerful spectroscopic techniques for probing magnetic properties in solids. In this study, we revisit the XMCD and XMLD sum rules within a complete magnetic multipole basis that incorporates both spinless and spinful multipoles. We demonstrate that these multipoles can be clearly distinguished and individually detected through the sum-rule formalism. Within this framework, the anisotropic magnetic dipole term is naturally derived in XMCD, offering a microscopic origin for ferromagnetic-like behavior in antiferromagnets. Furthermore, we derive the sum rules for out-of-plane and in-plane XMLD regarding electric quadrupole contributions defined based on the complete multipole basis. Our theoretical approach provides a unified, symmetry-consistent framework for analyzing dichroic signals in various magnetic materials. These findings deepen the understanding of XMCD and XMLD and open pathways to exploring complex magnetic structures and spin-orbit coupling effects in emergent magnetic materials.
X射线磁圆二色性（XMCD）和X射线磁线二色性（XMLD）是用于探测固体磁性的强大光谱技术。在本研究中，我们在一个完整的磁多极基中重新审视XMCD和XMLD求和规则，该基既包含无自旋多极也包含有自旋多极。我们证明，通过求和规则形式可以清楚地区分并单独检测这些多极。在此框架内，XMCD中自然导出了各向异性磁偶极项，为反铁磁体中铁磁样行为提供了微观起源。此外，我们推导了基于完整多极基定义的关于面外和面内XMLD中电四极贡献的求和规则。我们的理论方法为分析各种磁性材料中的二色性信号提供了一个统一的、对称一致的框架。这些发现加深了对XMCD和XMLD的理解，并为探索新兴磁性材料中的复杂磁结构和自旋轨道耦合效应开辟了途径。
