The temperature behavior of the first critical field B C1 of superconducting thin film samples can be determined with high accuracy using an inductive and contactless method. Driving a sinusoidal current in a single coil placed in front of the sample, a nonzero third harmonic voltage V 3 is induced in it when Abrikosov vortices enter the sample. Conditions to be satisfied for the quantitative evaluation of B C1 using this technique are detailed. As a validation test, different type II superconductors Nb, NbN, MgB 2 , and Y 1 Ba 2 Cu 3 O 7-d under the form of thin films have been measured. The comparison between experimental results, data presented in literature, and theoretical predictions is presented and discussed.
First critical field measurements of superconducting films by third harmonic analysis
G Lamura;A Andreone;
2009
Abstract
The temperature behavior of the first critical field B C1 of superconducting thin film samples can be determined with high accuracy using an inductive and contactless method. Driving a sinusoidal current in a single coil placed in front of the sample, a nonzero third harmonic voltage V 3 is induced in it when Abrikosov vortices enter the sample. Conditions to be satisfied for the quantitative evaluation of B C1 using this technique are detailed. As a validation test, different type II superconductors Nb, NbN, MgB 2 , and Y 1 Ba 2 Cu 3 O 7-d under the form of thin films have been measured. The comparison between experimental results, data presented in literature, and theoretical predictions is presented and discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
