Frąckowiak Łukasz, Kuświk Piotr, Chaves-O'Flynn Gabriel David, Urbaniak Maciej, Matczak Michał, Michałowski Paweł Piotr, Maziewski Andrzej, Reginka Meike, Ehresmann Arno, Stobiecki Feliks
Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland.
Faculty of Physics, University of Białystok, Ciołkowskiego 1L, 15-245 Białystok, Poland.
Phys Rev Lett. 2020 Jan 31;124(4):047203. doi: 10.1103/PhysRevLett.124.047203.
We show that it is possible to engineer magnetic multidomain configurations without domain walls in a prototypical rare-earth-transition-metal ferrimagnet using keV He^{+} ion bombardment. We additionally show that these patterns display a particularly stable magnetic configuration due to a deep minimum in the energy of the system caused by flux closure and a corresponding reduction of the magnetostatic energy without an increase in energy by exchange and anisotropy terms across the walls. This occurs because light-ion bombardment affects an element's relative contribution to the properties of the ferrimagnet differently. Therefore, it is possible to control the relative contribution from each magnetic subsystem. The selection of material and the use of light-ion bombardment allow us to engineer domain patterns in continuous magnetic films, which open a way to fabricate them in a much smaller scale than currently possible. Our Letter emphasizes that the right criterion to determine the presence or absence of a domain wall is whether there is a rotation of the spin for each sublattice and that changes of the direction of effective magnetization alone do not constitute an appropriate criterion.
我们表明，使用keV He⁺离子轰击，在典型的稀土 - 过渡金属铁氧体磁体中，可以设计出没有畴壁的磁性多畴结构。我们还表明，由于通量闭合导致系统能量出现深度最小值，以及静磁能相应降低，且壁间交换和各向异性项不会使能量增加，这些图案呈现出特别稳定的磁性结构。之所以会这样，是因为轻离子轰击对元素对铁氧体磁体性质的相对贡献有不同影响。因此，有可能控制每个磁子系统的相对贡献。材料的选择和轻离子轰击的使用使我们能够在连续磁性薄膜中设计畴图案，这为以比目前更小的规模制造它们开辟了一条道路。我们的信函强调，确定畴壁是否存在的正确标准是每个亚晶格的自旋是否有旋转，仅有效磁化方向的变化并不构成合适的标准。
