Abstract We report an unusual angular dependent magnetoresistance (ADMR) in single-crystalline Co films grown on Al2O3(0 0 0 1). The Co film with a thickness of 4.4 nm shows nearly zero anisotropic magnetoresistance for arbitrary magnetization orientations, and the sign of the ADMR reverses with changing Co thickness. By systematically measuring the Co-thickness-dependent anisotropic conductance in single-crystal Co/Pt, Pt/Co, and Pt/Co/Pt, we reveal that the ADMR of the Co layer grown on the Pt underlayer is significantly different from that of the Co layer grown on Al2O3(0 0 0 1). Our results suggest that the transport properties of the Co layer as a function of Pt thickness must be considered in order to better understand the spin Hall magnetoresistance in the Co/Pt bilayer.

中文翻译：

---

单晶 Co 膜和 Co/Pt 异质结构中厚度相关的角度相关磁阻

摘要 我们报告了在 Al2O3(0 0 0 1) 上生长的单晶 Co 膜中的不寻常的角度相关磁阻 (ADMR)。对于任意磁化方向，厚度为 4.4 nm 的 Co 膜显示出几乎为零的各向异性磁阻，并且 ADMR 的符号随着 Co 厚度的变化而反转。通过系统地测量单晶 Co/Pt、Pt/Co 和 Pt/Co/Pt 中 Co 厚度相关的各向异性电导，我们发现在 Pt 底层上生长的 Co 层的 ADMR 与在 Al2O3(0 0 0 1) 上生长的 Co 层。我们的结果表明，必须考虑 Co 层的传输特性作为 Pt 厚度的函数，以便更好地了解 Co/Pt 双层中的自旋霍尔磁阻。