Nanoscale detection and control of the magnetic order underpins a spectrum of condensed-matter research and device functionalities involving magnetism. The key principle involved is the breaking of time-reversal symmetry, which in ferromagnets is generated by an internal magnetization. However, the presence of a net magnetization limits device scalability and compatibility with phases, such as superconductors and topological insulators. Recently, altermagnetism has been proposed as a solution to these restrictions, as it shares the enabling time-reversal-symmetry-breaking characteristic of ferromagnetism, combined with the antiferromagnetic-like vanishing net magnetization^1,2,3,4. So far, altermagnetic ordering has been inferred from spatially averaged probes^{4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19}. Here we demonstrate nanoscale imaging of altermagnetic states from 100-nanometre-scale vortices and domain walls to 10-micrometre-scale single-domain states in manganese telluride (MnTe)^{2,7,9,14,15,16,18,20,21}. We combine the time-reversal-symmetry-breaking sensitivity of X-ray magnetic circular dichroism¹² with magnetic linear dichroism and photoemission electron microscopy to achieve maps of the local altermagnetic ordering vector. A variety of spin configurations are imposed using microstructure patterning and thermal cycling in magnetic fields. The demonstrated detection and controlled formation of altermagnetic spin configurations paves the way for future experimental studies across the theoretically predicted research landscape of altermagnetism, including unconventional spin-polarization phenomena, the interplay of altermagnetism with superconducting and topological phases, and highly scalable digital and neuromorphic spintronic devices^{3,14,22,23,24}.

磁序的纳米级检测和控制是涉及磁性的凝聚态研究和器件功能的基础。所涉及的关键原理是打破时间反转对称性，在铁磁体中，这种对称性是由内部磁化产生的。然而，净磁化强度的存在限制了器件的可扩展性和与相（如超导体和拓扑绝缘体）的兼容性。最近，交替磁性被提出作为这些限制的解决方案，因为它具有铁磁性的使能时间反转对称性打破特性，并结合了反铁磁性样消失净磁化^1,2,3,4。到目前为止，已从空间平均探针^{4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19} 中推断出互磁排序。在这里，我们展示了碲化锰 （MnTe） 中从 100 纳米级涡流和畴壁到 10 微米级单畴状态的交替磁态的纳米级成像^{2,7,9,14,15,16,18,20,21}。我们将 X 射线磁圆二色性¹² 的时间反转对称性打破灵敏度与磁线性二色性和光发射电子显微镜相结合，以实现局部交替磁排序向量的映射。使用微结构图案化和磁场中的热循环施加各种自旋配置。 已证明的互通磁自旋构型的检测和受控形成为未来理论预测的互通磁研究领域的实验研究铺平了道路，包括非常规的自旋极化现象、互通互通与超导和拓扑相的相互作用，以及高度可扩展的数字和神经形态自旋电子器件^{3,14,22,23,24}。