Study of the vortex dynamic in MgB2 by harmonic susceptibility measurements

C. Senatore*, M. Polichetti, D. Zola, T. Di Matteo, S. Pace, G. Giunchi, S. Ceresara, G. Ripamonti

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


In order to investigate the flux line dynamic in the recently discovered MgB2 superconductor, we have measured the ac magnetic susceptibility as a function of the temperature T and the ac field frequency f on a bulk sample. In particular we have analysed the fundamental and the third harmonics X1,3(T) = iX′1,3(T) + iX′′(T) by comparison of the experimental data with both analytical and numerical results. We show that in the temperature range below Tp(X′′1) (i.e. the peak temperature of the imaginary part for the fundamental harmonic) the measured curves for X3(T) do not agree with the curves predicted by the Bean model for the critical state, and that the shape of the third harmonic, both in the real and the imaginary part, is strongly affected by the frequency f, as a consequence of the thermally activated vortex motion in a non linear flux diffusion regime. The evidence of this behaviour allows one to estimate the value of the pinning barrier for the analysed sample.

Original languageEnglish
Pages (from-to)655-660
Number of pages6
JournalInternational Journal of Modern Physics B
Issue number4-6 I
Publication statusPublished - 10 Mar 2003
Externally publishedYes


Dive into the research topics of 'Study of the vortex dynamic in MgB2 by harmonic susceptibility measurements'. Together they form a unique fingerprint.

Cite this