论文标题
在合成抗铁磁铁中破坏对称性诱导的磁杆磁耦合
Symmetry breaking induced magnon-magnon coupling in synthetic antiferromagnets
论文作者
论文摘要
我们提出了一种用于对称性合成反铁磁铁（SAFS）的微波吸收光谱的一般理论。通常，SAF的两个铁磁性子层的不均匀性或不同的厚度会导致内在的对称性破裂，而直流磁场的平面成分导致外部磁场。 SAFS的破碎对称性不包括纯粹的对称性跨相和相反的平均值之间的原始对称性保护的交叉。或者，新的频率分支成为原始裸模式的杂交，从对称性诱导的磁杆磁通耦合方面，这导致铁磁共振频率的间接差距。同样，介绍了差距宽度对几种典型情况的对称性破坏程度的依赖性，并与现有实验进行了比较。我们的理论对非对称SAF的铁磁共振光谱的丰富结构提供了简单但物理的理解。
We propose a general theory of microwave absorption spectroscopy for symmetry-breaking synthetic antiferromagnets (SAFs). Generally, inhomogeneity or different thickness of the two ferromagnetic sublayers of a SAF results in the intrinsic symmetry breaking, while out-of-plane components of dc magnetic fields lead to the extrinsic one. The broken symmetry of SAFs excludes the original symmetry-protected crossing between pure in-phase and out-of-phase resonance modes with opposite parity. Alternatively, new frequency branches become hybridization of original bare modes in terms of symmetry-breaking-induced magnon-magnon coupling, which results in an indirect gap in ferromagnetic resonance frequencies. Also, the dependence of gap width on the degree of symmetry breaking for several typical cases are presented and compared with existing experiments. Our theory provides a simple but physical understanding on the rich structure of ferromagnetic resonance spectra for asymmetric SAFs.
