Analysis of the Ghost and Mirror Fields in the Nernst Signal Induced by Superconducting Fluctuations

Abstract

We present a complete analysis of the Nernst signal due to superconducting fluctuations in a large variety of superconductors from conventional to unconventional ones. A closed analytical expression of the fluctuation contribution to the Nernst signal is obtained in a large range of temperature and magnetic field. We apply this expression directly to experimental measurements of the Nernst signal in Nb${}_x$Si${}_{1-x}$ thin films and a URu${}_2$Si${}_2$ superconductors. Both magnetic field and temperature dependence of the available data are fitted with very good accuracy using only two fitting parameters, the superconducting temperature $T_{c0}$ and the upper critical field $H_{c2}$. The obtained values agree very well with experimentally obtained values. We also extract the ghost lines (maximum of the Nernst signal for constant temperature or magnetic field) from the complete expression and also compare it to several experimentally obtained curves. Our approach predicts a linear temperature dependence for the ghost critical field well above $T_{c0}$. Within the errors of the experimental data, this linearity is indeed observed in many superconductors far from $T_{c0}$.

8 pages, 8 figures, 1 table

References in corpus (5)

• Decrease of upper critical field with underdoping in cuprate superconductors
• Giant Nernst Effect due to Fluctuating Cooper Pairs in Superconductors
• Colossal thermomagnetic response in the exotic superconductor URu2Si2
• A length scale for the superconducting Nernst signal above T${}_c$ in Nb${}_{0.15}$Si${}_{0.85}$
• Nernst effect in the electron-doped cuprate superconductor PCCO: Superconducting fluctuations, upper critical field Hc2, and the origin of the Tc dome

Cited by in corpus (3)

• Vortex entropy and superconducting fluctuations in ultrathin underdoped Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+x}$ superconductor
• Nernst effect and its thickness dependence in superconducting NbN films
• Microwave Signature of the Emerging Abrikosov Lattice Above $H_{c2}$