CoPt-NbN和NbN-CoPt超导-铁磁体异质结构中晶格失配引起的颗粒度：应变的影响

非均匀涡旋态驱动的纳米铁磁-超导异质结构超导电性增强

Inhomogeneous vortex-state-driven enhancement of superconductivity in nanoengineered ferromagnet-superconductor heterostructures

薄膜异质结构为研究超导性与铁磁性之间的对抗提供了有力的手段。在FM-SC混合体中，一个有趣的问题是观察到磁场诱导的超导性（FIS），这违背了对抗顺序的概念。在这里，我们表明，在系统中的FM域/岛产生的SC序参量的空间不均匀性，FIS可以从不同的迁移率的磁通量确定的两个不同的临界状态在非均匀超导体中的显着贡献。我们的实验纳米工程双层铁磁CoPt和超导NbN的CoPt/NbN岛分开的颗粒NbN，借给支持这种替代解释FIS在某些类别的FM-SC混合。

NbN薄膜中颗粒感生的无带隙超导电性：热相位涨落的证据

Granularity-induced gapless superconductivity in NbN films: evidence of thermal phase fluctuations

利用单线圈互感技术，测量了具有相似临界温度（16 K）但不同微结构的NbN超导薄膜的磁穿透深度随温度的变化。只有（100）外延和弱颗粒（100）织构薄膜显示出传统BCS s波超导体的特征指数依赖性。更多的颗粒状（111）织构薄膜表现出线性相关性，表明无带隙状态，尽管s波间隙。这一结果是定量解释的颗粒状结构有利于热相波动的模型。

Complex phase-fluctuation effects correlated with granularity in superconducting NbN nanofilms

Superconducting nanofilms are tunable systems that can host a 3D-2D dimensional crossover, leading to the Berezinskii-Kosterlitz-Thouless (BKT) superconducting transition approaching the 2D regime. Reducing further the dimensionality, from 2D to quasi-1D, superconducting nanostructures with disorder can generate quantum and thermal phase slips (PS) of the order parameter. Both BKT and PS are complex phase fluctuation phenomena of difficult experimental detection. Here, we have characterized superconducting NbN nanofilms thinner than 15 nm, on different substrates, by temperature dependent resi…

Effect of impurity scattering on percolation of bosonic islands and reentrant superconductivity in Fe implanted NbN thin films

A reentrant temperature dependence of the thermoresistivity $ρ_{\mathrm{xx}}(T)$ between an onset local superconducting ordering temperature $T_\mathrm{loc}^\mathrm{onset}$ and a global superconducting transition at $T=T_\mathrm{glo}^\mathrm{offset}$ has been reported in disordered conventional 3-dimensional (3D) superconductors. The disorder of these superconductors is a result of either an extrinsic granularity due to grain boundaries, or of an intrinsic granularity ascribable to the electronic disorder originating from impurity dopants. Here, the effects of Fe doping on the electronic prope…

Spectroscopic evidence for strong correlations between local superconducting gap and local Altshuler-Aronov density-of-states suppression in ultrathin NbN films

Disorder has different profound effects on superconducting thin films. For a large variety of materials, increasing disorder reduces electronic screening which enhances electron-electron repulsion. These fermionic effects lead to a mechanism described by Finkelstein: when disorder combined to electron-electron interactions increases, there is a global decrease of the superconducting energy gap $Δ$ and of the critical temperature $T_c$, the ratio $Δ$/$k_BT_c$ remaining roughly constant. In addition, in most films an emergent granularity develops with increasing disorder and results in the forma…