Topological swirling spin textures, such as skyrmions and merons, have recently attracted much attention as potential building blocks for high-density magnetic information devices. Controlling the transformation between different types of these quasiparticles is an important challenge. To date, these transitions have mostly been limited to a few non-centrosymmetric systems, where they are driven by the Dzyaloshinskii–Moriya interaction. Here we demonstrate multistep topological transitions among a variety of meron and skyrmion crystal states in a centrosymmetric magnet GdRu₂Ge₂. These are governed by the competition between Ruderman–Kittel–Kasuya–Yosida interactions at inequivalent wave vectors. These findings demonstrate that even a simple centrosymmetric magnet with competing interactions can be a promising material platform to realize a richer variety of magnetic quasiparticles with distinctive symmetry and topology, whose stability can be tuned by various external stimuli.

拓扑漩涡自旋纹理，例如斯格明子和梅子，最近作为高密度磁信息设备的潜在构建模块而引起了广泛关注。控制这些不同类型的准粒子之间的转变是一个重要的挑战。迄今为止，这些转变大多局限于一些非中心对称系统，它们是由 Dzyaloshinskii-Moriya 相互作用驱动的。在这里，我们展示了中心对称磁体 GdRu ₂ Ge ₂中各种米子和斯格明子晶态之间的多步拓扑转变。这些是由鲁德曼-基特尔-卡苏亚-吉田相互作用在不等波矢量下的竞争决定的。这些发现表明，即使是具有竞争相互作用的简单中心对称磁体也可以成为一个有前途的材料平台，以实现更丰富的具有独特对称性和拓扑结构的磁性准粒子，其稳定性可以通过各种外部刺激来调节。