反铁磁（AFM）材料已被广泛用于制造高温超导、拓扑绝缘体、庞磁阻等具有特别重要物性的材料。但目前对AFM的研究很少且主要集中在宏观层面，微观成像研究很少。主要因为：1 AFM畴净磁矩接近0，难被作用、探测和调控；2 AFM相从产生到消亡过程需较强磁场。但微观成像研究很重要，毕竟很多重要物性和畴界、形态、钉扎、弛豫、动态行为与调控方式直接相关。本项目将对AFM相在温度、磁场调控下的动力学行为进行高分辨成像研究，并探索膜厚、掺杂、应力等因素对AFM相畴及其子畴行为的影响。我们研制的20T-ALL-MFM的磁场达20T，频率分辨达亚毫赫兹，完全胜任本项目，国际上尚无此类装置。我们用其对PCMO的初步研究就观测到0-17.6T内AFM相从融化到重生的完整过程，显示该装置的强大。作为探索，我们还将尝试将其升级为频率分辨率再提高3个量级的20T-PFE-MFM，用于研究相畴内的子畴结构及行为。

Antiferromagnetic (AFM) materials have been widely used in the manufacture of high temperature superconductors, topological insulators, colossal magneto-resistance materials and other materials with particularly important physical properties. However, very few studies on AFM, most of them focused on the macro level, studies on the microscopic imaging even fewer. This is mainly because: (1) the net magnetic moment of the AFM domains is approximately equal to zero, which is difficult to be detected and controlled; (2) the process of the AFM phase from birth to extinction is driven by a strong magnetic field. But microscopic imaging studies are very important, after all, a lot of important physical properties are related to microscopic domain boundaries, shape, pinning, relaxation, dynamic behavior and control directly. In this project, we will study the dynamics behavior of the AFM phase by high resolution microscopic imaging which was controlled by temperature and magnetic field, and explore the impact of the film thickness, doping, relaxation, stress, current and other factors on the behavior of the AFM domains and sub-domains. We have developed a 20T-ALL-MFM with the magnetic field up to 20T and sub-mini hertz frequency resolution, which can fully competent in this project. There is no such device in the world now. We have used this device conducted a preliminary study on the Pr0.5Ca0.5MnO3/LSAT, and observed the complete process of the antiferromagnetic phase from melt to rebirth under high magnetic field within 0-17.6T, which shows the strong capability of the device. As an exploration, we will also try to upgrade the 20T-ALL-MFM to the 20T-PFE-MFM which increase the frequency resolution of the order of 3. The new 20T-PFE-MFM will be used to study the structure and behavior of the sub-domain of the AFM phase domain.