Shimamoto Y, Matsushima Y, Hasegawa T, Kousaka Y, Proskurin I, Kishine J, Ovchinnikov A S, Goncalves F J T, Togawa Y
Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan.
Department of Physics and Electronics, Osaka Metropolitan University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan.
Phys Rev Lett. 2022 Jun 17;128(24):247203. doi: 10.1103/PhysRevLett.128.247203.
A chiral spin soliton lattice (CSL), one of the representative systems of a magnetic superstructure, exhibits reconfigurability in periodicity over a macroscopic length scale. Such coherent and tunable characteristics of the CSL lead to an emergence of elementary excitation of the CSL as phononlike modes due to translational symmetry breaking and bring a controllability of the dispersion relation of the CSL phonon. Using a broadband microwave spectroscopy technique, we directly found that higher-order magnetic resonance modes appear in the CSL phase of a chiral helimagnet CrNb_{3}S_{6}, which is ascribed to the CSL phonon response. The resonance frequency of the CSL phonon can be tuned between 16 and 40 GHz in the vicinity of the critical field, where the CSL period alters rapidly. The frequency range of the CSL phonon is expected to extend over 100 GHz as extrapolated on the basis of the theoretical model. The present results indicate that chiral helimagnets could work as materials useful for broadband signal processing in the millimeter-wave band.
手性自旋孤子晶格（CSL）是磁性超结构的代表性系统之一，在宏观长度尺度上表现出周期性的可重构性。CSL的这种相干且可调谐的特性导致由于平移对称性破缺而出现类似声子模式的CSL元激发，并带来CSL声子色散关系的可控性。利用宽带微波光谱技术，我们直接发现手性螺旋磁体CrNb₃S₆的CSL相中出现了高阶磁共振模式，这归因于CSL声子响应。在临界场附近，CSL声子的共振频率可以在16至40GHz之间调谐，此时CSL周期会迅速变化。根据理论模型推断，CSL声子的频率范围有望扩展到100GHz以上。目前的结果表明，手性螺旋磁体可作为用于毫米波波段宽带信号处理的有用材料。
