Fabrication and transport properties of superconducting thin films
Problem of periodicity, symmetry and finite dimensions of S/F multilayers
Superconductivity in layered systems is closely related to the spatial behavior of the order parameter. In recent years the influence of finite dimensions of superconductor/normal metal (S/N) multilayers on the superconducting phase nucleation has been studied [1-3]. In particular the finiteness of multilayers with a variable number of bilayers (Nbil) determines the position of the symmetry plane of the samples. For odd Nbil, in fact, the symmetry plane lies in the central S layer (S-type samples), while for even N_bil it is located in the normal metal layer (N-type samples). Moreover the multilayers finiteness requires to take into account the strong influence of the sample edges imposing appropriate boundary conditions in the Ginzburg-Landau (GL) equations. In the framework of this model it was shown that the position where the superconducting phase nucleates affects, for example, the resistive transition to the superconducting state, the shape of the H(T) phase diagram as well as the Hc2(q) dependence in S/N multilayers, where Nb is the superconducting material and Cu and Pd are the normal ones.
More recently this study was extended to the case of S/F multilayers [4-6]. In these systems, in fact, the possible realization of the so called "p-phase" makes this investigation even more appealing. The samples under study consist of high quality Nb/PdNi multilayers with fixed layers thicknesses (dNb=18.7 nm, dPdNi=2.2 nm) and variable number of bilayers. Preliminary theoretical simulations showed that the correlation between the spatial distribution of the superconducting wave function and both the resistive R(T) transitions of the samples and the critical temperature behavior Tc(Nbil) of the series.
[1] V.N. Kushnir, S.L. Prischepa, M.L. Della Rocca, M. Salvato, and C. Attanasio, Phys. Rev. B 68, 212505 (2003)
[2] V.N. Kushnir, S.L. Prischepa, C. Cirillo, M.L. Della Rocca, A. Angrisani Armenio, L. Maritato, M. Salvato, and C. Attanasio, EPJB 41, 439 (2004)
[3] S.L. Prischepa, C. Cirillo, V.N. Kushnir, M. Salvato, and C. Attanasio, Phys. Rev. B 72, 24535 (2005)
[4] S.L. Prischepa, V.N. Kushnir, E.A. Ilyna, C. Attanasio, C. Cirillo, G. Iannone, A. Vecchione, R. Fittipaldi, and J. Aarts. Physics, Chemistry and Application of Nanostructures. Nanomeeting 2007, Minsk, Bielorussia
[5] S.L. Prischepa, C. Cirillo, C. Bell, V.N. Kushnir, J. Aarts, C. Attanasio, and M. Yu. Kupriyanov, JETP Letters 88, 375 (2008)
[6] V.N. Kushnir, S.L. Prischepa, C. Cirillo, C. Attanasio, M. Yu. Kupriyanov, and J. Aarts, in preparation
[7] E.A. Ilyina, C. Cirillo, S.L. Prischepa, C. Attanasio, J. Supercond. Nov. Magn. 23, 329 (2010)
[8] V. N. Kushnir, S. L. Prischepa, C. Cirillo, and C. Attanasio, J. Appl. Phys. 106, 113917 (2009)
[9] D. Mancusi, E. A. Ilyina, V. N. Kushnir, S. L. Prischepa, C. Cirillo, and C. Attanasio, in preparation.