Frequency in Middle of Magnon Band Gap in a Layered Ferromagnetic Superlattice

• 来源期刊: 理论物理通讯(英文版)
• 学科: 物理学
• 关键词: 铁磁超晶格 磁振子 层间交换耦合 自旋量子数 频率效应 中频 带隙 格林函数方法
• 年，卷（期）: 2010,（12）
• 页码范围: 1144-1150
• 页数: 7页
• 分类号: O482.5 O737
• 语种: 英文

摘要

The frequency in middle of magnon energy band in a five-layer ferromagnetic superlattice is studied byusing the linear spin-wave approach and Green's function technique.It is found that four energy gaps and correspondingfour frequencie in middle of energy gaps exist in the magnon band along Kx direction perpendicular to the superlatticeplane.The spin quantum numbers and the interlayer exchange couplings all affect the four frequencies in middle of theenergy gaps.When all interlayer exchange couplings are same, the effect of spin quantum numbers on the frequency ωg1in middle of the energy gap Δω12 is complicated, and the frequency ωg1 depends on the match of spin quantum numbersin each layer.Meanwhile, the frequencies ωg2, ωg3, and ωg4 in middle of other energy gaps increase monotonously withincreasing spin quantum numbers.When the spin quantum numbers in each layer are same, the frequencies ωg1, ωg2,ωg3, and ωg4 all increase monotonously with increasing interlayer exchange couplings.