论文标题
6 MeV质子辐照对BAFE $ _ {2} $中涡旋合奏的影响（AS $ _ {0.67} $ P $ _ {0.33} $ _ 2 $ _ 2 $通过磁化测量和真实的空间涡流成像揭示
Effects of 6 MeV proton irradiation on the vortex ensemble in BaFe$_{2}$(As$_{0.67}$P$_{0.33}$)$_2$ revealed through magnetization measurements and real-space vortex imaging
论文作者
论文摘要
Bafe $ _ {2} $中涡旋合奏的变化（AS $ _ {0.67} $ p $ _ {0.33} $）$ _ 2 $，一种基于掺杂的铁的超导体（IBS），通过全球磁化测量值和单个Vortex Imageing和单个Vortex Imageing进行了研究，并在6 mev Proton之后进行了研究。通过强钉模型分析了临界电流密度（$ j_ \ mathrm {c} $）的场依赖性，原始样本与该模型保持一致。辐照后，$ j_ \ mathrm {c} $从$ b^{ - 5/8} $的强钉场依赖性中差，并演变成较弱的$ b^{ - 1/3} $依赖性，具有异常的两步性两步行为，创造出类似的功能。尖端与局部最小值的域相吻合，以归一化的松弛速率（$ s $），这是由于Interveex相互作用增加而导致的固定量增加，其次是由较高场上的通量激活引起的快速涡流动力学。此外，单个涡旋成像表明，虽然在原始样品中观察到abrikosov涡旋晶格的远程三角形相关性，但辐照样品表现出高度无序的玻璃状涡流状态，这更密集地挤满了增加的固定力。这些通过质子辐照掺入的人造缺陷具有与掺杂掺杂相同的固定效应，这不仅将固定力转移到更高的程度，而且还扩大了其分布，与P掺杂相反，Poping仅拓宽了固定分布而不会诱导移位。总而言之，通过这项调查，我们对Bafe $ _ {2} $中的固定行为提供了系统的理解（AS $ _ {0.67} $ P $ _ {0.33} $）$ _ 2 $通过仔细控制系统中的缺陷。
The change in vortex ensemble in BaFe$_{2}$(As$_{0.67}$P$_{0.33}$)$_2$, an isovalently doped iron-based superconductor (IBS), is studied through global magnetization measurements and single vortex imaging before and after 6 MeV proton irradiation. The field dependence of the critical current density ($J_\mathrm{c}$) is analyzed through the strong pinning model, with which the pristine sample is consistent. After the irradiation, the $J_\mathrm{c}$ aberrates from the strong pinning field dependence of $B^{-5/8}$, and evolves to a weaker $B^{-1/3}$ dependence with an anomalous two-step behavior creating a cusp like feature. The cusp coincides with the field of the local minima in the normalized relaxation rate ($S$), manifested by increased pinning due to increased intervortex interactions followed by fast vortex dynamics caused by flux activation at higher fields. Furthermore, single vortex imaging reveals that while long-range triangular correlation of the Abrikosov vortex lattice is observed in pristine samples, irradiated samples exhibit a highly disordered glassy vortex state which is more densely packed with increased pinning force. These artificial defects incorporated via proton irradiation have the same pinning effect as Co doping which not only shifts the pinning force to a higher degree but also broadens its distribution, in contrast to P doping which only broadens the pinning distribution without inducing a shift. All in all, through this investigation, we provide a systematic understanding of the pinning behavior in BaFe$_{2}$(As$_{0.67}$P$_{0.33}$)$_2$ through carefully controlling the defects in the system.
