Magnetic excitations in helimagnets over a broad range of spin-spiral pitch lengths.

该项目的目的是了解具有自旋螺旋或Skyrmion有序的手性磁性材料中的Helimon激发的低能自旋动力学。我们将研究几个具有非常不同的自旋螺旋间距的化合物，或者，如果在倒易空间中观察，则具有不同的不可公度参数，这些参数相对于之前研究的参考化合物MnSi要么更长，要么更短。一方面，通常用标准中子衍射法测量的非共线磁体具有相对较短的螺旋结构周期，在几个原子间距离的数量级上，如在Sr3Fe2O7或ZnCr2Se4的情况下。另一方面，天空离子-晶格系统中典型的长螺距螺旋结构，如B20化合物或Cu2OSeO_3，属于小角中子散射仪的适用范围。我们的结果有望跨越这两个极端之间的广泛的自旋结构，并扩展到可能具有更长螺旋间距的新材料。

The aim of the proposed project is to understand the low-energy spin dynamics of helimagnon excitations in chiral magnetic materials exhibiting spin-spiral or skyrmion order. We will investigate several compounds characterized by very different pitches of the spin helix or, if viewed in the reciprocal space, by different incommensurability parameters that are either longer and shorter with respect to the previously studied reference compound MnSi. On the one hand, noncollinear magnets that are typically measured by standard neutron diffraction possess relatively short periods of the spiral structure on the order of several interatomic distances, as in the case of Sr3Fe2O7 or ZnCr2Se4. On the other hand, long-pitch helical structures typical for skyrmion-lattice systems, such as B20 compounds or Cu2OSeO3, fall in the applicability range of small-angle neutron scattering instruments. Our results are expected to span the broad range of spin structures between these two extremes and extend to new materials with possibly even longer helix pitches.