Vortex dynamics in YBa2Cu3O7- delta superconducting films: Experimental evidence for an instability in the vortex system at high current densities.
Vortex dynamics in YBa2Cu3O7- delta superconducting films: Experimental evidence for an instability in the vortex system at high current densities.
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YBa2Cu3O7-δ 超导薄膜中的涡流动力学：高电流密度下涡流系统不稳定的实验证据。
DOI：
10.1103/physrevb.53.15265
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Ziemann
中科院分区：
文献类型：
--
作者：
Xiao;Ziemann
研究了YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}薄膜在高达5 T的磁场下的电流-电压特性和电阻率的温度依赖关系。在给定磁场下，当电流密度和温度分别达到临界值{ital J}{sup{星号}}和{ital T}{sup{星号}}时，可以观察到高驱动力下的电压和电阻率的跳变。通过用{ital J}{sup{星号}}({ital H},{ital T})={ital J}{sup{星号}}({ital T})/(1+{ital H}/{ital H}{下标0}){sup {alpha}}和{ital J}{sup{星号}}({ital T}){近似}(1{负}{ital T}/{ital T}{下标c}0}){sup 3/2}，以1/3{le}{alpha}{le}3/4、{ital H}{下标0}和{ital T}{下标c}0}作为常数来描述场和温度的依赖关系，获得了很好的缩放实验数据。这些结果表明了一个定义明确的旋涡不稳定性，与Larkin和Ovchinnikov （LO）对高通量流速度的预测非常相似。然而，在目前的情况下，通过参考电流-电压（{ital I}-{ital V}）特性，可以证明这种不稳定性即使在远低于{ital T}{次{ital g}}的温度下也会发生，该温度是通过将负弯曲的{ital I}-{ital V}特性与正弯曲的{ital I}-{ital V}特性分开来定义的。根据LO理论对实验观察到的不稳定性进行了分析，得到了非弹性准粒子散射时间与温度的关系。作为一个新的方面，对于小磁场，相应的临界通量流速度表现出显著的场依赖性，而对于大于2 T的磁场，这种依赖性似乎消失了。{版权所有}{ital 1996美国物理学会。}«少
Current-voltage characteristics and the temperature dependence of the electrical resistivity of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thin films were investigated in magnetic fields up to 5 T. For a given magnetic field, both voltage and resistivity jumps could be observed at high driving forces when the current density and the temperature reached the critical values {ital J}{sup {asterisk}} and {ital T}{sup {asterisk}}, respectively. Excellent scaling of the experimental data was obtained by describing the field and temperature dependence by {ital J}{sup {asterisk}}({ital H},{ital T})={ital J}{sup {asterisk}}({ital T})/(1+{ital H}/{ital H}{sub 0}){sup {alpha}} and {ital J}{sup {asterisk}}({ital T}){approximately}(1{minus}{ital T}/{ital T}{sub {ital c}0}){sup 3/2} with 1/3{le}{alpha}{le}3/4 and {ital H}{sub 0} and {ital T}{sub {ital c}0} being constants. These results indicate a well-defined vortex instability closely resembling that predicted by Larkin and Ovchinnikov (LO) for high flux flow velocities. In the present case, however, by referring to the current-voltage ({ital I}-{ital V}) characteristics, this instability can be demonstrated to occur even at temperatures well below {ital T}{sub {ital g}} defined by separating negatively from positively curved {ital I}-{ital V} characteristics. Analyzing the experimentally observed instability according to LO theory, the temperature dependence of the inelastic quasiparticle scattering time has been obtained. As a new aspect,more » the corresponding critical flux-flow velocity exhibits a significant field dependence for small magnetic fields, while for fields above 2 T this dependence seems to disappear. {copyright} {ital 1996 The American Physical Society.}« less