Topological Signatures in the Hall Effect of SrRuO3/La0.7Sr0.3MnO3 SLs
Topological Signatures in the Hall Effect of SrRuO3/La0.7Sr0.3MnO3 SLs
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DOI：
10.1002/pssb.201900628
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发表时间：
2019-12
期刊：
影响因子：
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通讯作者：
M. Ziese;F. Bern;P. Esquinazi;I. Lindfors-Vrejoiu
中科院分区：
文献类型：
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作者：
M. Ziese;F. Bern;P. Esquinazi;I. Lindfors-Vrejoiu
非共线自旋纹理（例如斯格明子）会产生一种新颖的霍尔效应，称为拓扑霍尔效应。近年来，研究主要集中在 Weyl 金属 SrRuO3 上，其拓扑特征报告为与具有强自旋轨道耦合的层相邻的 SrRuO3 层。然而，众所周知，SrRuO3 薄膜在与不同材料接触时容易发生结构变化。在这项工作中，SrRuO3/La0.7Sr0.3MnO3 超晶格 (SL) 的霍尔效应与结构和磁性信息相关，以研究拓扑霍尔效应是否是通过与铁磁层连接而引起的。通过脉冲激光沉积在 SrTiO3 基底上制造具有超薄层的高质量 SL。通过角磁阻测量研究 SrRuO3 层的对称性，通过磁化测量研究磁晶各向异性。详细比较了两种 SL，两者均具有 8 个晶胞厚度的 SrRuO3 层，但 La0.7Sr0.3MnO3 层具有 2 和 4 个晶胞厚度。只有具有 2 个晶胞厚的锰酸盐层的样品才显示出类似于拓扑霍尔效应的特征。根据 La0.7Sr0.3MnO3 层厚度，SrRuO3 晶体对称性为斜方晶系或四方晶系。结果表明，拓扑霍尔效应特征是由磁晶各向异性和反铁磁层间耦合之间复杂的相互作用产生的。
Noncollinear spin textures such as skyrmions lead to a novel Hall effect contribution called the topological Hall effect. In recent years, research has focused on the Weyl metal SrRuO3 with topological signatures reported for SrRuO3 layers adjacent to layers with strong spin–orbit coupling. However, SrRuO3 films are known to be prone to structural modifications when interfaced with different materials. In this work the Hall effect of SrRuO3/La0.7Sr0.3MnO3 superlattices (SLs) is correlated with structural and magnetic information to study whether a topological Hall effect is induced by interfacing to ferromagnetic layers. High‐quality SLs with ultrathin layers are fabricated by pulsed laser deposition on SrTiO3 substrates. The symmetry of the SrRuO3 layers is studied by angular magnetoresistance measurements and the magnetocrystalline anisotropy by magnetization measurements. Two SLs are compared in detail, both with 8 unit cell thick SrRuO3 layers, but with La0.7Sr0.3MnO3 layers 2 and 4 unit cell thick. Only the sample with 2 unit cell thick manganite layers shows features resembling a topological Hall effect. Depending on the La0.7Sr0.3MnO3 layer thickness the SrRuO3 crystalline symmetry is orthorhombic or tetragonal. The results indicate that the topological Hall effect features arise from an intricate interplay between magnetocrystalline anisotropy and antiferromagnetic interlayer coupling.