Perpendicular magnetic anisotropy (PMA) in magnetic thin films is a fundamental key feature in the design of spintronic devices. As one of magnetic Weyl semimetals, ${\mathrm{Co}}_3{\mathrm{Sn}}_2{\mathrm{S}}_2$ has been studied for its large anomalous Hall effect (AHE), uniaxial crystalline magnetic anisotropy, and half metallicity. In this study, we investigated the effect of off-stoichiometric composition on the PMA and AHE of ${\mathrm{Co}}_3{\mathrm{Sn}}_2{\mathrm{S}}_x$ thin films fabricated by the sputtering technique. The prepared thin films have off-stoichiometric S compositions $x$ of 1.54 (S poor) and 3.27 (S rich) as well as the nearly stoichiometric one of 2.02. In addition to the ${\mathrm{Co}}_3{\mathrm{Sn}}_2{\mathrm{S}}_2$ phase, the segregated Co metal is found to contribute to the measured magnetization in the S-poor and S-rich films. The coercive field of perpendicular magnetization in all the films is much larger than that in the ${\mathrm{Co}}_3{\mathrm{Sn}}_2{\mathrm{S}}_2$ bulk crystals despite the fact that effective perpendicular magnetic anisotropy constants ($K_{\mathrm{u}}^{\mathrm{eff}}$) between the prepared films are significantly different. In addition, the $K_{\mathrm{u}}^{\mathrm{eff}}$ values of two samples with $x=2.02$ and 2.22 are comparable to those of the bulk crystals. In contrast to the isotropic magnetization behavior in the S-rich film, the S-poor film holds the PMA feature. This result means that the PMA is more robust in the S-poor film than in the S-rich film. For the electrical transport properties, a large tangent of Hall angle of about 0.2 is observed for both the nearly stoichiometric and the S-poor films. This large tangent of Hall angle demonstrates that the Weyl feature of ${\mathrm{Co}}_3{\mathrm{Sn}}_2{\mathrm{S}}_2$ phase is well maintained even in the S-poor thin films as well as the nearly stoichiometric films although the amount of Co segregation in both S-poor and S-rich films is similar. Our findings on the influence of off-stoichiometry on the PMA and AHE are beneficial to design magnetic devices incorporated with the Weyl features of ${\mathrm{Co}}_3{\mathrm{Sn}}_2{\mathrm{S}}_2$.

中文翻译：

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缺硫溅射薄膜中Co3Sn2S2相的强垂直磁各向异性

磁性薄膜中的垂直磁各向异性（PMA）是自旋电子器件设计的基本关键特征。作为磁性Weyl半金属之一，${\mathrm{有限公司}}_3{锡}_2{\mathrm{小号}}_2$由于其大的异常霍尔效应（AHE），单轴晶体磁各向异性和半金属性，已经对其进行了研究。在这项研究中，我们调查了非化学计量组成对PMA和AHE的影响。${\mathrm{有限公司}}_3{锡}_2{\mathrm{小号}}_X$通过溅射技术制造的薄膜。制备的薄膜具有非化学计量比的S组成$X$1.54（低硫）和3.27（高硫），以及接近化学计量的2.02。除了${\mathrm{有限公司}}_3{锡}_2{\mathrm{小号}}_2$相中，发现偏析的钴金属有助于贫S和富S膜中测得的磁化强度。所有薄膜的垂直磁化矫顽场都比薄膜中的大。${\mathrm{有限公司}}_3{锡}_2{\mathrm{小号}}_2$ 尽管有效垂直磁各向异性常数（${ķ}_{\mathrm{ü}}^{效}$）之间的准备的电影有很大的不同。除此之外${ķ}_{\mathrm{ü}}^{效}$ 两个样本的值 $X=2.02$和2.22与块状晶体相当。与富S膜中的各向同性磁化行为相反，贫S膜具有PMA功能。该结果意味着，贫S膜中的PMA比富S膜中的PMA更坚固。对于电传输性能，对于几乎化学计量的膜和S贫化的膜，霍尔角的正切值均约为0.2。霍尔角的大切线表明${\mathrm{有限公司}}_3{锡}_2{\mathrm{小号}}_2$尽管贫S薄膜和富S薄膜中的Co偏析量相似，但即使在贫S薄膜以及接近化学计量的薄膜中也能很好地保持相平衡。我们关于化学计量失衡对PMA和AHE的影响的发现有助于设计结合了Weyl特性的磁性器件${\mathrm{有限公司}}_3{锡}_2{\mathrm{小号}}_2$。