Manna Sujit, Przybylski M, Sander D, Kirschner J
Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
J Phys Condens Matter. 2016 Nov 16;28(45):456001. doi: 10.1088/0953-8984/28/45/456001. Epub 2016 Sep 9.
We demonstrate the interplay between quantum well states in Pd and the magnetic anisotropy in Pd/Co/Cu (0 0 1) by combined scanning tunneling spectroscopy (STS) and magneto optical Kerr effect (MOKE) measurements. Low temperature scanning tunneling spectroscopy reveals occupied and unoccupied quantum well states (QWS) in atomically flat Pd films on Co/Cu (0 0 1). These states give rise to sharp peaks in the differential conductance spectra. A quantitative analysis of the spectra reveals the electronic dispersion of the Pd (0 0 1) d-band ([Formula: see text]-type) along the [Formula: see text]-X direction. In situ MOKE experiments on Pd/Co/Cu (1, 1, 13) uncover a periodic variation of the in-plane uniaxial magnetic anisotropy as a function of Pd thickness with a period of 6 atomic layers Pd. STS shows that QWS in Pd cross the Fermi level with the same periodicity of 6 atomic layers. Backed by previous theoretical work we ascribe the variation of the magnetic anisotropy in Co to QWS in the Pd overlayer. Our results suggest a novel venue towards tailoring uniaxial magnetic anisotropy of ferromagnetic films by exploiting QWS in an adjacent material with large spin-orbit coupling.
我们通过结合扫描隧道谱（STS）和磁光克尔效应（MOKE）测量，展示了钯（Pd）中的量子阱态与Pd/Co/Cu（0 0 1）中的磁各向异性之间的相互作用。低温扫描隧道谱揭示了在Co/Cu（0 0 1）上原子级平整的Pd薄膜中的占据和未占据量子阱态（QWS）。这些态在微分电导谱中产生尖锐的峰。对谱的定量分析揭示了Pd（0 0 1）d带（[公式：见正文]型）沿[公式：见正文]-X方向的电子色散。对Pd/Co/Cu（1, 1, 13）进行的原位MOKE实验发现，面内单轴磁各向异性随Pd厚度呈周期性变化，周期为6个Pd原子层。STS表明，Pd中的QWS以相同的6个原子层周期穿过费米能级。基于先前的理论工作，我们将Co中磁各向异性的变化归因于Pd覆盖层中的QWS。我们的结果表明了一种新途径，即通过利用具有大自旋轨道耦合的相邻材料中的QWS来定制铁磁薄膜的单轴磁各向异性。
