In the left side picture FC magnetic moment value below zero but in right side it is above zero. Could you kindly tell me what is the reason?In case of superconductor material.
The positive Field Cool (FC), deviating from Meissner effect with the negative FC, was theoretically predicted as effect of Josephson-pi junction [M. Sigrist and T. M. Rice, J. Phys. Soc. Jpn. 61 (1992) 4283]. The josephson-pi junction was suggested as evidence of d-wave pairing symmetry for cuprate superconductors. The FC was measured in cuprate superconductors. However, it was also observed in s-wave superconductors such as Nb, BKBO etc. The FC had been intensively studied in the middle of 1990s. Most researchers have believed that the positive FC comes from trap of magnetic flux not Josephson-pi junction. Moreover, as for the high-Tc mechanism of cuprate superconductors, would you please see my answer in a question ‘Why BCS theory of superconductivity can't explain the behavior of HTSC like YBCO ???”.
The references on the positive FC are given below.
[1] Hyun-Tak Kim, https://arxiv.org/pdf/cond-mat/0206432.pdf
[2] U.Welp et al., Physica C 235-240 (1994) 241
[3] J. Kötzler, M. Baumann, and N. Knauf, Phys. Rev. B 52 (1995) 1215
[4] S. Riedling et al., Phys. Rev. B 49 (1994) 13283(R)
[5] P. Kostić et al., Phys. Rev. B 53 (1996) 791
Answer: May 7, 2018
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