Pankratova M, Eriksson O, Bergman A
Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden.
Wallenberg Initiative Materials Science for Sustainability, Uppsala University, 75121 Uppsala, Sweden.
J Phys Condens Matter. 2024 Jun 26;36(38). doi: 10.1088/1361-648X/ad5598.
We report on the stabilization of ferromagnetic skyrmions in zero external magnetic fields, in exchange-biased systems composed of ferromagnetic-antiferromagnetic (FM-AFM) bilayers. By performing atomistic spin dynamics simulations, we study cases of compensated, uncompensated, and partly uncompensated FM-AFM interfaces, and investigate the impact of important parameters such as temperature, inter-plane exchange interaction, Dzyaloshinskii-Moriya interaction, and magnetic anisotropy on the skyrmions appearance and stability. The model with an uncompensated FM-AFM interface leads to the stabilization of individual skyrmions and skyrmion lattices in the FM layer, caused by the effective field from the AFM instead of an external magnetic field. Similarly, in the case of a fully compensated FM-AFM interface, we show that FM skyrmions can be stabilized. We also demonstrate that accounting for interface roughness leads to stabilization of skyrmions both in compensated and uncompensated interface. Moreover, in bilayers with a rough interface, skyrmions in the FM layer are observed for a wide range of exchange interaction values through the FM-AFM interface, and the chirality of the skyrmions depends critically on the exchange interaction.
我们报道了在由铁磁-反铁磁（FM-AFM）双层组成的交换偏置系统中，零外磁场下铁磁斯格明子的稳定性。通过进行原子自旋动力学模拟，我们研究了补偿、未补偿和部分未补偿的FM-AFM界面的情况，并研究了温度、面间交换相互作用、Dzyaloshinskii-Moriya相互作用和磁各向异性等重要参数对斯格明子出现和稳定性的影响。具有未补偿FM-AFM界面的模型导致FM层中单个斯格明子和斯格明子晶格的稳定，这是由AFM的有效场而非外磁场引起的。同样，在完全补偿的FM-AFM界面的情况下，我们表明FM斯格明子可以被稳定。我们还证明，考虑界面粗糙度会导致补偿和未补偿界面中的斯格明子都得到稳定。此外，在具有粗糙界面的双层中，通过FM-AFM界面在很宽的交换相互作用值范围内都观察到了FM层中的斯格明子，并且斯格明子的手性严格取决于交换相互作用。
