Shi Xiaohui, Jiang Jiawei, Wang Yadong, Hou Zhipeng, Zhang Qiang, Mi Wenbo, Zhang Xixiang
Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin 300354, China.
Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China.
ACS Appl Mater Interfaces. 2021 Jun 9;13(22):26639-26648. doi: 10.1021/acsami.1c07098. Epub 2021 May 27.
Noncollinear spin textures have attracted much attention due to their novel physical behaviors in heavy/ferromagnetic metal (HM/FM) systems. The transport anomaly, appearing as contrast humps in Hall resistivity curves, is the mark of noncollinear spin textures. Here, the epitaxial Pt/γ'-FeN bilayers with noncollinear spin textures were obtained by facing target sputtering. Large micromagnetic Dzyaloshinskii-Moriya interaction coefficient of 2.90 mJ/m appears in Pt/γ'-FeN/MgO systems, which is larger than 2.05 mJ/m of Pt/Co/MgO systems with skyrmionic states. Moreover, at 300 K, magnetic bubble-like domains appear in Pt/γ'-FeN bilayers that just possess a 3 nm thick ferromagnetic layer instead of [HM/FM] or [HM/FM/HM] multilayers. Additionally, a room-temperature transport anomaly appears in Pt/γ'-FeN/MgO systems. The contrast humps of Pt(3 nm)/γ'-FeN( ≤ 4 nm)/MgO heterostructures are not sharp due to the nonuniform distributions of the magnetic bubble-like domains with various sizes and irregular shapes, as observed by the magnetic force microscopy. The discovery of epitaxial Pt/γ'-FeN bilayers with noncollinear spin states is more crucial than that of polycrystalline or amorphous HM/FM systems for reducing ohmic heating, which provides a candidate for noncollinear spintronic applications.
非共线自旋纹理因其在重/铁磁金属（HM/FM）系统中的新颖物理行为而备受关注。作为霍尔电阻率曲线中的对比峰出现的输运异常是非共线自旋纹理的标志。在此，通过面对靶溅射获得了具有非共线自旋纹理的外延Pt/γ'-FeN双层膜。在Pt/γ'-FeN/MgO系统中出现了2.90 mJ/m的大微磁Dzyaloshinskii-Moriya相互作用系数，该系数大于具有斯格明子态的Pt/Co/MgO系统的2.05 mJ/m。此外，在300 K时，在仅具有3 nm厚铁磁层而非[HM/FM]或[HM/FM/HM]多层膜的Pt/γ'-FeN双层膜中出现了磁泡状畴。另外，在Pt/γ'-FeN/MgO系统中出现了室温输运异常。如通过磁力显微镜观察到的，由于具有各种尺寸和不规则形状的磁泡状畴的不均匀分布，Pt(3 nm)/γ'-FeN(≤4 nm)/MgO异质结构的对比峰不尖锐。对于减少欧姆热而言，具有非共线自旋态的外延Pt/γ'-FeN双层膜的发现比多晶或非晶HM/FM系统的发现更为关键，这为非共线自旋电子学应用提供了一个候选材料。
