Ferrimagnetic thin films are attractive for low-power spintronic applications because of their low magnetization, small angular momentum, and fast spin dynamics. Spin orbit torques (SOT) can be applied with proximal heavy metals that also generate interfacial Dzyaloshinskii–Moriya interactions (DMI), which can stabilize ultrasmall skyrmions and enable fast domain wall motion. Here, the properties of a ferrimagnetic CoGd alloy between two heavy metals to increase the SOT efficiency, while maintaining a significant DMI is studied. SOT switching for various capping layers and alloy compositions shows that Pt/CoGd/(W or Ta) films enable more energy-efficient SOT magnetization switching than Pt/CoGd/Ir. Spin-torque ferromagnetic resonance confirms that Pt/CoGd/W has the highest spin-Hall angle of 16.5%, hence SOT efficiency, larger than Pt/CoGd/(Ta or Ir). Density functional theory calculations indicate that CoGd films capped by W or Ta have the largest DMI energy, 0.38 and 0.32 mJ m⁻², respectively. These results show that Pt/CoGd/W is a very promising ferrimagnetic structure to achieve small skyrmions and to move them efficiently with current.

中文翻译：

---

亚铁磁性非晶合金中自旋轨道扭矩和 Dzyaloshinskii-Moriya 相互作用之间的相互作用

亚铁磁性薄膜因其低磁化、小角动量和快速自旋动力学而对低功率自旋电子应用具有吸引力。自旋轨道扭矩 (SOT) 可以与近端重金属一起应用，这些重金属也会产生界面 Dzyaloshinskii-Moriya 相互作用 (DMI)，这可以稳定超小斯格明子并实现快速畴壁运动。在这里，研究了两种重金属之间的亚铁磁 CoGd 合金的特性，以提高 SOT 效率，同时保持显着的 DMI。各种覆盖层和合金成分的 SOT 切换表明，与 Pt/CoGd/Ir 相比，Pt/CoGd/（W 或 Ta）薄膜能够实现更节能的 SOT 磁化切换。自旋扭矩铁磁共振证实 Pt/CoGd/W 具有 16.5% 的最高自旋霍尔角，因此 SOT 效率，大于 Pt/CoGd/（Ta 或 Ir）。密度泛函理论计算表明，W 或 Ta 覆盖的 CoGd 薄膜具有最大的 DMI 能量，分别为 0.38 和 0.32 mJ m^-2，分别。这些结果表明，Pt/CoGd/W 是一种非常有前途的亚铁磁结构，可以实现小斯格明子并通过电流有效地移动它们。