2005/04/21 by Jinho Kim, Jun Hyung Kwon, Jun Kwon +3 · 1 citation
Physics and Astronomy · #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Superconductivity in MgB2 and Alloys #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.72.014518
10 pages, 5 figures and 1 table
arxiv created 2005/04/21 · openalex publication_date 2005/07/12 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We have studied the behavior of the superconducting critical temperature Tc in Nb∕Co60Fe40, Nb∕Ni, and Nb∕Cu40Ni60 bilayers as a function of the thickness of each ferromagnetic metal layer. The Tc's of three sets of bilayers exhibit nonmonotonic behavior as a function of each ferromagnetic metal thickness. Employing the quantitative analysis based on Usadel formalism of the effect of the exchange energy, we observed that the Tc behavior of Nb∕Co60Fe40 bilayers is in good agreement with the theoretical values over the entire range of the data. On the other hand, the Tc's of Nb∕Ni and Nb∕Cu40Ni60 bilayers show a higher value in the small thickness regime than the theoretical prediction obtained from the calculation, which matches the dip position and the saturation value of Tc in the large thickness limit. This discrepancy is probably due to the weakened magnetic properties of Ni and Cu40Ni60 when they are thin. We discuss the values of our fitting parameters and their implication for the validity of the current Usadel formalism of the effect of the exchange energy.