Fogt Joseph, Weeda Hope, Harrison Trevor, Miles Nolan, Cho Kyuil
Department of Physics, Hope College, Holland, MI 49423, USA.
Materials (Basel). 2024 Sep 19;17(18):4601. doi: 10.3390/ma17184601.
We investigated the effect of 0.6 MeV proton irradiation on the superconducting and normal-state properties of thin-film YBa2Cu3O7-δ superconductors. A thin-film YBCO superconductor (≈567 nm thick) was subject to a series of proton irradiations with a total fluence of 7.6×1016 p/cm2. Upon irradiation, Tc was drastically decreased from 89.3 K towards zero with a corresponding increase in the normal-state resistivity above Tc. This increase in resistivity, which indicates an increase in defects inside the thin-film sample, can be converted to the dimensionless scattering rate. We found that the relation between Tc and the dimensionless scattering rate obtained during proton irradiation approximates the generalized d-wave Abrikosov-Gor'kov theory better than the previous results obtained from electron irradiations. This is an unexpected result, since the electron irradiation is known to be most effective to suppress superconductivity over other heavier ion irradiations such as proton irradiation. In comparison with the previous irradiation studies, we found that the result can be explained by two facts. First, the dominant defects created by 0.6 MeV protons can be point-like when the implantation depth is much longer than the sample thickness. Second, the presence of defects on all element sites is important to effectively suppress Tc.
我们研究了0.6兆电子伏特质子辐照对薄膜YBa2Cu3O7-δ超导体超导和正常态特性的影响。对一个薄膜YBCO超导体（约567纳米厚）进行了一系列质子辐照，总注量为7.6×1016 p/cm2。辐照后，Tc从89.3 K急剧降至零，同时高于Tc的正常态电阻率相应增加。这种电阻率的增加表明薄膜样品内部缺陷增加，可转换为无量纲散射率。我们发现，质子辐照期间获得的Tc与无量纲散射率之间的关系比之前电子辐照获得的结果更符合广义d波阿布里科索夫-戈尔科夫理论。这是一个意想不到的结果，因为已知电子辐照在抑制超导性方面比其他重离子辐照（如质子辐照）更有效。与之前的辐照研究相比，我们发现该结果可以由两个事实来解释。第一，当注入深度远大于样品厚度时，0.6兆电子伏特质子产生的主要缺陷可能是点状的。第二，所有元素位点上缺陷的存在对于有效抑制Tc很重要。
