Magnetic skyrmion and its derivatives have demonstrated fascinating topological behaviors with potential applications in future spintronic devices. Despite the recent progress, the spontaneous skyrmion lattice and successive topological transition in the magnets with easy-plane magnetic anisotropy are still elusive especially at room temperature. Here, in a centrosymmetric rhombohedral Nd₂Co₁₇ magnet with easy-plane magnetic anisotropy, spontaneous biskyrmions are observed over a wide temperature range across room temperature, and then evolve into enclosed in-plane domains with nanometric size due to the enhancement of the planar magnetic anisotropy. The spontaneous generation of the biskyrmion lattice and its evolution along different crystal orientations demonstrate the crucial role of intrinsic bi-anisotropy and demagnetization effects. This discovery provides a fundamental insight into the nature of topological magnetic textures in easy-plane anisotropy materials and suggests an arena to explore the topological states in rare-earth magnets as well as their applications in spintronics.

中文翻译：

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具有易平面各向异性的中心对称菱面体稀土磁体中的自发Biskyrmion晶格

磁性斯格明子及其衍生物展示了迷人的拓扑行为，在未来的自旋电子器件中具有潜在应用。尽管最近取得了进展，但具有易平面磁各向异性的磁体中的自发斯格明子晶格和连续拓扑转变仍然难以捉摸，尤其是在室温下。这里，在一个中心对称的菱形 Nd ₂ Co ₁₇在具有易平面磁各向异性的磁体中，在室温的宽温度范围内观察到自发的双斯格米子，然后由于平面磁各向异性的增强而演变成具有纳米尺寸的封闭面内畴。biskyrmion 晶格的自发生成及其沿不同晶体方向的演化证明了固有双各向异性和退磁效应的关键作用。这一发现提供了对易平面各向异性材料中拓扑磁结构性质的基本见解，并为探索稀土磁体中的拓扑状态及其在自旋电子学中的应用提供了一个舞台。