AI 中文总结
研究CoPd合金及多层膜中氢诱导的磁滞现象，通过反常霍尔效应表征发现氢响应依赖成分和层厚，存在磁滞回线收缩、扩展及极性反转等情况，揭示了氢可通过电子和磁弹效应选择性调磁，为相关器件提供见解。
AI 中文摘要
磁性薄膜纳米结构中的氢吸收可通过改变电子结构和晶格应变来调节其电子、磁性和输运性质。然而，成分和纳米结构对这两种竞争效应的影响尚未得到很好的理解。我们系统地研究了Co$_x$Pd$_{100 - x}$合金、[Co(0.1 nm)/Pd(d)]$_{15}$和[Co(0.2 nm)/Pd(d)]$_{15}$多层膜中氢诱导的磁滞现象，使用了在空气和4% H$_2$/N$_2$混合物中的反常霍尔效应表征（EHE）。我们表明，氢诱导的响应并非普遍存在，而是强烈依赖于成分和层厚度。这反映了Pd相关电子效应和磁弹各向异性之间的竞争。在富Pd的CoPd合金和Co(0.2 nm)/Pd多层膜中，氢在低Co分数下最初使磁滞回线收缩，随后在x ~ 40%以上使回线扩展。这种对比源于通过Pd - 4d带填充抑制Pd诱导的磁化与氢驱动的各向异性应变之间的竞争，后者在富Co样品中增强了磁弹各向异性。相比之下，在超薄的[Co(0.1 nm)/Pd(d)]$_{15}$多层膜中，氢在x = 15 - 60%范围内诱导出微弱、非单调但总体上扩展的回线行为，表明在超薄极限下界面磁连通性和应变介导的磁弹各向异性起主导作用。此外，我们在交叉区域附近观察到氢诱导的EHE回线极性反转，反映了主导EHE散射机制发生变化，并提供了额外的氢磁可调性。这些结果表明，氢可以通过成分控制的电子和磁弹效应选择性地调节CoPd纳米结构的磁性，为氢响应自旋电子和传感装置提供了见解。
英文摘要
Hydrogen absorption in magnetic thin film nanostructures can modulate their electronic, magnetic, and transport properties by modifying the electronic structure and lattice strain. However, the influence of composition and nanostructuring on these two competing effects is not well understood. We systematically investigate hydrogen-induced magnetic hysteresis in Co$_x$Pd$_{100-x}$ alloys, [Co(0.1 nm)/Pd(d)]$_{15}$, and [Co(0.2 nm)/Pd(d)]$_{15}$ multilayers, using extraordinary Hall effect characterizations (EHE) in air and 4% H$_2$/N$_2$ mixture. We show that the hydrogen-induced response is not universal, but depends strongly on composition and layer thickness. This reflects competition between Pd-related electronic effects and magnetoelastic anisotropy. In Pd-rich CoPd alloys and Co(0.2 nm)/Pd multilayers, hydrogen initially contracts the hysteresis loops at low Co fractions, followed by loop expansion above x ~ 40%. This contrast results from competition between suppression of Pd-induced magnetization through Pd-4d band filling and hydrogen-driven anisotropic strain that strengthens magnetoelastic anisotropy in Co-rich samples. In contrast, in ultrathin [Co(0.1 nm)/Pd(d)]$_{15}$ multilayers, hydrogen induces a weak, non-monotonic but generally expanding loop behaviour across x = 15-60%, indicating a dominant role of interfacial magnetic connectivity and strain-mediated magnetoelastic anisotropy in the ultrathin limit. Furthermore, we observe a hydrogen-induced reversal of the EHE loop polarity near the crossover regime, reflecting a change in the dominant EHE scattering mechanisms, thus providing an additional degree of magnetic tunability by hydrogen. These results demonstrate that hydrogen can selectively tune the magnetism of CoPd nanostructures via composition-controlled electronic and magnetoelastic effects, offering insights for hydrogen-responsive spintronic and sensing devices.
Comments49 pages, 8 main figures; Supplementary Material included
Journal refJournal of Alloys and Compounds 1078 (2026) 189655
DOI：10.1016/j.jallcom.2026.189655
