T4 to T2 resistivity transition and superconducting fluctuations in disordered VN films.
T4 to T2 resistivity transition and superconducting fluctuations in disordered VN films.
复制标题
无序 VN 薄膜中 T4 到 T2 电阻率转变和超导波动。
DOI：
10.1103/physrevb.38.5065
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Vaglio
中科院分区：
文献类型：
--
作者：
Zasadziński;Saggese;Gray;Kampwirth;Vaglio
制备的VN薄膜具有广泛的结构无序，其特征是从Rho/sub0/=5.0的净值剩余电阻率。厘米到100亩盖欧米茄..厘米。这种无序现象主要是由于制得的薄膜中的氮空位或清洁的化学计量比的VN的粒子损伤所致。我们观察到随着无序度的增加，低温电阻率的幂函数关系从T/sup 4/到T/sup 2/的转变，这与Gurvitch提出的强耦合超导体的普遍行为是一致的。将这种跃迁与普适作图进行比较，得到了电子-声子耦合λ/subp/之间的估计值在1.0和1.1之间。无序薄膜还表现出比T/subc/高几度的电导率增强，这可以用三维(3D)超导涨落模型很好地描述。这代表了在3D薄膜中观察到涨落增强导电性的少数情况之一，其他情况是高T/subc/氧化物，如YBA/sub2/Cu/sub3/O/sub7/。
Thin films of Vn have been prepared with a wide range of structural disorder as characterized by residual resistivities from the clean value of rho/sub 0/ = 5.0 ..mu cap omega.. cm up to 100 ..mu cap omega.. cm. The disorder is primarily a consequence of nitrogen vacancies in as-made films or ..cap alpha..-particle damage of clean, stoichiometric VN. We have observed a transition in the power-law dependence of the low-temperature resistivity from T/sup 4/ to T/sup 2/ as disorder increases, consistent with the universal behavior of strong-coupled superconductors proposed by Gurvitch. Comparison of this transition with the universal plot leads to an estimate of the electron-phonon coupling lambda/sub p/ between 1.0 and 1.1. Disordered films also display an enhanced conductivity several degrees above T/sub c/ which is well described by a model of three-dimensional (3D) superconducting fluctuations. This represents one of the few cases where fluctuation enhanced conductivity has been observed in 3D films, other cases being the high-T/sub c/ oxides such as YBa/sub 2/Cu/sub 3/O/sub 7/.