The flux-flow hall effect in type II superconductors. An explanation of the sign reversal

Sign change of the flux flow Hall effect in HTSC

“…We will follow the approach developed in [15] where it was proposed that the imaginary part of the relaxation Then the δn contribution to the Hall conductivity in Eq. (9) coincides with the result of [13,14] if the numerical parameter β (−α 2 in notation of [13]) is equal to 1, which corresponds to the value of the TDGL parameter u ≪ 1 [14]. For large values of u the analysis of [13,14] gives a similar result but with an additional coefficient of the order of unity in front of the 'δn' term.…”

“…We will show now that the δn term in the conductvity we found is just the term which was obtained in Time Dependent Ginzburg Landau (TDGL) model [13,14]. We will follow the approach developed in [15] where it was proposed that the imaginary part of the relaxation Then the δn contribution to the Hall conductivity in Eq.…”

“…Near H c2 (T ) ω 0 ≈ cyclotron freqyuency ω c , thus the first term in Eq. (11) transforms to the normal state Hall conductivity σ n xy , whereas the 'δn' contribution goes to zero ∝ H c2 − H, and the Hall effect changes sign back to the normal value in this region [14]. These are just the two sign changes observed in Bi and Tl based materials.…”

Anomalous scaling behavior in a mixed-state Hall effect of a cobalt-doped BaFe2As2epitaxial film with a high critical current density over 1 MA/cmSato1, Katase2, Kang3 et al. 2013Phys. Rev. B17170View full textAdd to dashboardCite

“…Matsuda et al [48] and Nagaoka et al [49] have experimentally suggested that the sign of ρ xy depends on the doping level in most cuprate superconductors; i.e., a sign reversal occurs in an underdoped regime but diminishes in overdoped ones. Kopnin et al [50] and Dorsey [51] have also discussed the Hall anomaly based on a microscopic approach and proposed theories of a mixed-state Hall effect based on a time-dependent Ginzburg-Landau model; they postulate that the sign reversal depends on the gradient of the density of states at the Fermi surface. According to these experimental and theoretical results, researching the doping concentration dependence may provide a definitive conclusion on the Hall sign reversal in high-J c BaFe 2 As 2 :Co epitaxial films because this study employed a slightly overdoped sample.…”

Hall voltage sign reversal in type II superconductors

“…The experimentally observed dependence of the Hall conductivity on magnetic field [35,36] also confirms our results (eq. 19),where a term independent on magnetic field is added in contrast to the previous theories [37,38]. Without any special assumption about pinning strength or fluctuations as was made by Wang et al [39] the theoretical curves qualitatively explain experimental results of the Hall effect of superconductors in the mixed state.…”