Magnetic anisotropy is a fundamental key parameter of magnetic materials that determines their applications. For ferromagnetic materials, the magnetic anisotropy can be easily detected by using conventional magnetic characterization techniques. However, due to the magnetic compensated structure in antiferromagnetic materials, synchrotron measurements, such as X-ray magnetic linear dichroism, are often needed to probe their magnetic properties. In this work, we observed an imprinted fourfold magnetic anisotropy in the amorphous ferromagnetic layer of FeRh/CoFeB heterostructures. The MOKE and ferromagnetic resonance measurements show that the easy magnetization axes of the CoFeB layer are along the FeRh〈110〉 and FeRh〈100〉 directions for the epitaxially grown FeRh layer in the antiferromagnetic and ferromagnetic states, respectively. The combined Monte Carlo simulation and first-principles calculation indicate that the fourfold magnetic anisotropy of the amorphous CoFeB layer is imprinted due to the interfacial exchange coupling between the CoFeB and FeRh moments from the magnetocrystalline anisotropy of the epitaxial FeRh layer. This observation of imprinting the magnetocrystalline anisotropy of antiferromagnetic materials on easily detected ferromagnetic materials may be applied to probe the magnetic structures of antiferromagnetic materials without using synchrotron methods.

磁各向异性是决定其应用的磁性材料的基本关键参数。对于铁磁材料，可以通过使用常规的磁表征技术轻松检测磁各向异性。然而，由于反铁磁性材料中的磁性补偿结构，经常需要同步加速器测量（例如X射线磁性线性二向色性）来探测其磁性。在这项工作中，我们观察到FeRh / CoFeB异质结构的非晶铁磁层中有一个印记的四倍磁各向异性。MOKE和铁磁共振测量结果表明，对于外延生长的FeRh层，在反铁磁和铁磁状态下，CoFeB层的易磁化轴分别沿FeRh <110>和FeRh <100>方向。组合的蒙特卡罗模拟和第一性原理计算表明，由于外延FeRh层的磁晶各向异性引起的CoFeB和FeRh矩之间的界面交换耦合，非晶态CoFeB层的四倍磁各向异性被压印。将反铁磁材料的磁晶各向异性压印在易于检测的铁磁材料上的观察结果可用于探测反铁磁材料的磁性结构，而无需使用同步加速器方法。