论文标题
标准的BCC CO $ _ {1-X} $ MN $ _X $ _x $基于磁性磁力隧道连接的高隧道磁力和磁性
High tunnel magnetoresistance and magnetism in metastable bcc Co$_{1-x}$Mn$_x$-based magnetic tunnel junctions
论文作者
论文摘要
共同富裕的CO $ _ {1-X} $ MN $ _x $合金具有HCP或FCC无序阶段，而这些铁磁秩序随着MN浓度$ x $的散装而大大恶化。另一方面，那些亚稳态的BCC相显示了对旋转的特性，例如，在磁性隧道连接（MTJ）中，在300 K（10 K）的高隧道磁场（TMR）比为200％以上（600％），$ x $ = 0.25 BCC Alloy Electrodes [Kunimimatsu等。物理。 Express 13，083007（2020）]。在这里，我们报告了在MGO（001） - 隔间MTJ中的结构和磁性的系统研究以及带有这些BCC膜的电极的TMR效应。单相BCC CO $ _ {1-X} $ MN $ _X $（001）胶片是在CR（001）上以0.14 <$ x $ <0.50在CR上生长的，并使用溅射技术生长。磁化强度大于$ x $ = 0.14-0.25的磁化磁化强度，并以进一步的增加$ x $去世。这种行为主要源自Mn的磁矩的组成依赖性，该磁矩在最大值上超过2 $μ_b$，这是X射线磁性圆形二科主义揭示的。相应地，在0.25 <$ x $ <0.37的范围内，TMR比从620％（229％）下降到10 K（300 K）的450％（194％），$ x $增加。我们在Ab-Initio频段结构计算的帮助下讨论了磁力和高TMR比与不同的$ x $之间的关系。
Co-rich Co$_{1-x}$Mn$_x$ alloys have hcp or fcc disordered phases and those ferromagnetic orderings are significantly deteriorated with increasing Mn concentration $x$ in bulk. On the other hand, those metastable bcc phases show properties attractive to spintronics, e.g., high tunnel magnetoresistance (TMR) ratio of more than 200% (600%) at 300 K (10 K) in magnetic tunnel junctions (MTJs) with the $x$ = 0.25 bcc alloy electrodes [Kunimatsu et al., Appl. Phys. Express 13, 083007 (2020)]. Here, we report systematic study of structure and magnetism for epitaxial thin films as well as the TMR effect in MgO(001)-barrier MTJs with electrodes comprising those bcc films. The single phase bcc Co$_{1-x}$Mn$_x$(001) films were pseudomorphically grown on Cr(001) for 0.14 < $x$ < 0.50 with a sputtering technique. The magnetization was larger than that of pure Co for $x$ = 0.14-0.25 and deceased with further increasing $x$. This behavior mainly stemmed from the composition dependence of magnetic moment of Mn that exceeded 2 $μ_B$ at the maximum, unveiled by X-ray magnetic circular dichroism. Correspondingly, within the range of 0.25 < $x$ < 0.37, the TMR ratio decreased from 620% (229%) to 450% (194%) at 10 K (300 K) as $x$ increased. We discussed the relationship between the magnetism and high TMR ratio with different $x$ with the aid of the ab-initio band structure calculations.
