论文标题
从植入的$β$ -Emitter $β$^{8} $ li的niobium薄膜中，Meissner筛选曲线的深度分辨测量
Depth-resolved measurement of the Meissner screening profile in a niobium thin film from spin-lattice relaxation of the implanted $β$-emitter $^{8}$Li
论文作者
论文摘要
我们报告了使用$^{8} $^{8} $ li $β$β$检测到的核磁共振（$β$ -NMR）的NB（300 nm）/al $ _ {2} $ o $ $ $ $ $ $ _ {3} $薄膜的测量值。 NMR探针$^{8} $ li在Energies $ \ leq $ 20 keV中被离子置于NB膜中，这对应于与NB的磁性渗透深度$λ$相当的停止深度。 $^{8} $ li的强偶极 - 偶极 - 与主机$^{93} $ nb nuclei提供了一个“交叉解释”通道，该通道以低磁场为主导，通过旋转局部磁场（SLR）速率（SLR）速率（SLR）速率$ 1/T_ $ 1/T_ 1/T_ 1} $ {1} $ {1} $。从$ 1/t_ {1} $数据的拟合到模型，以占其依赖温度，磁场和$^{8} $ li $^{+} $植入能量，我们获得了磁性渗透深度$λ_{0} $ = 51.5（22）NM，与相对短的$ fre-free-Path $ uneme nme nm nme n nmem n nmm use n $ unem unem unem unem unem uph $ nmmm。类似准备的NB电影。此处介绍的结果构成了使用$^{8} $ li $β$ -NMR来表征具有工程表面的散装NB样品的重要一步，这些样本通常用于制造粒子加速器。
We report measurements of the Meissner screening profile in a Nb(300 nm)/Al$_{2}$O$_{3}$ thin film using $^{8}$Li $β$-detected nuclear magnetic resonance ($β$-NMR). The NMR probe $^{8}$Li was ion-implanted into the Nb film at energies $\leq$ 20 keV, corresponding to mean stopping depths comparable to Nb's magnetic penetration depth $λ$. $^{8}$Li's strong dipole-dipole coupling with the host $^{93}$Nb nuclei provided a "cross-relaxation" channel that dominated in low magnetic fields, which conferred indirect sensitivity to the local magnetic field via the spin-lattice relaxation (SLR) rate $1/T_{1}$. From a fit of the $1/T_{1}$ data to a model accounting for its dependence on temperature, magnetic field, and $^{8}$Li$^{+}$ implantation energy, we obtained a magnetic penetration depth $λ_{0}$ = 51.5(22) nm, consistent with a relatively short carrier mean-free-path $\ell$ = 18.7(29) nm typical of similarly prepared Nb films. The results presented here constitute an important step towards using $^{8}$Li $β$-NMR to characterize bulk Nb samples with engineered surfaces, which are often used in the fabrication of particle accelerators.
