Tacchi S, Troncoso R E, Ahlberg M, Gubbiotti G, Madami M, Åkerman J, Landeros P
Istituto Officina dei Materiali del CNR (CNR-IOM), Sede Secondaria di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, I-06123 Perugia, Italy.
Departamento de Física, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso, Chile.
Phys Rev Lett. 2017 Apr 7;118(14):147201. doi: 10.1103/PhysRevLett.118.147201. Epub 2017 Apr 3.
We report the observation of a Pt layer thickness dependence on the induced interfacial Dzyaloshinskii-Moriya interaction in ultrathin Pt(d_{Pt})/CoFeB films. Taking advantage of the large spin-orbit coupling of the heavy metal, the interfacial Dzyaloshinskii-Moriya interaction is quantified by Brillouin light scattering measurements of the frequency nonreciprocity of spin waves in the ferromagnet. The magnitude of the induced Dzyaloshinskii-Moriya coupling is found to saturate to a value of 0.45 mJ/m^{2} for Pt thicknesses larger than ∼2 nm. The experimental results are explained by analytical calculations based on the three-site indirect exchange mechanism that predicts a Dzyaloshinskii-Moriya interaction at the interface between a ferromagnetic thin layer and a heavy metal. Our findings open up a way to control and optimize chiral effects in ferromagnetic thin films through the thickness of the heavy-metal layer.
我们报告了关于超薄Pt(dPt)/CoFeB薄膜中Pt层厚度对诱导界面Dzyaloshinskii-Moriya相互作用的依赖性的观察结果。利用重金属的大自旋轨道耦合,通过对铁磁体中自旋波频率非互易性的布里渊光散射测量来量化界面Dzyaloshinskii-Moriya相互作用。对于厚度大于约2nm的Pt,诱导的Dzyaloshinskii-Moriya耦合强度被发现饱和到0.45 mJ/m²的值。实验结果通过基于三位点间接交换机制的解析计算得到解释,该机制预测了铁磁薄层与重金属之间界面处的Dzyaloshinskii-Moriya相互作用。我们的发现为通过重金属层的厚度来控制和优化铁磁薄膜中的手性效应开辟了一条途径。