Discrete model analysis of the critical current-density measurements in superconducting thin films by a single-coil inductive method
Discrete model analysis of the critical current-density measurements in superconducting thin films by a single-coil inductive method
复制标题
单线圈感应法超导薄膜临界电流密度测量的离散模型分析
DOI：
10.1063/1.2142097
复制
发表时间：
2005
影响因子：
3.2
通讯作者：
A. Andreone
中科院分区：
文献类型：
--
作者：
M. Aurino;E. D. Gennaro;F. D. Iorio;A. Gauzzi;G. Lamura;A. Andreone
超导膜的临界电流密度可以很容易地用感应和非接触方法测定。在放置在超导样品前的单个线圈中驱动正弦电流，当样品超过Bean临界状态时，在其中诱导非零三次谐波电压V3。V3的开始标志着电流的值，超过该值，样品对磁感应的响应不再是线性的。为了真实地考虑到薄膜和线圈之间的磁耦合，我们建立了感应电流和感应电流分布的离散模型。在此模型框架下，计算了样品表面的磁场分布、线圈内电流与超导薄膜临界电流密度JC的关系系数。以几种已知超导性质的YBa2Cu3O7−δ薄膜作为对照材料，通过测量其JC对数值结果进行了验证。
The critical current density of a superconducting film can be easily determined by an inductive and contactless method. Driving a sinusoidal current in a single coil placed in front of a superconducting sample, a nonzero third-harmonic voltage V3 is induced in it when the sample goes beyond the Bean critical state. The onset of V3 marks the value of current beyond which the sample response to the magnetic induction is no more linear. To take into account, in a realistic way, the magnetic coupling between the film and the coil, we have developed a discrete model of the inducing and induced currents distribution. In the framework of this model the magnetic-field profile on the sample surface and the coefficient linking the current flowing in the coil and the critical current density JC of superconducting thin films are evaluated. The numerical results are checked by measuring JC of several thin films of YBa2Cu3O7−δ of known superconducting properties, used as a control material.