Non-conventional superconducting fluctuations in Ba(Fe1-xRhx)2As2 iron-based superconductors

We measured the static uniform spin susceptibility of Ba(Fe$_{1-x}$Rh$_x$)$_2$As$_2$ iron-based superconductors, over a broad range of doping ($0.041\leq x\leq 0.094$) and magnetic fields. At small fields ($H \le$ 1 kOe) we observed, above the transition temperature $T_c$, the occurrence of precursor diamagnetism, which is not ascribable to the Ginzburg-Landau theory. On the contrary, our data fit a phase fluctuation model, which has been used to interpret a similar phenomenology occurring in the high-$T_c$ cuprate superconductors. On the other hand, in presence of strong fields the unconventional fluctuating diamagnetism is suppressed, whereas 3D fluctuations are found, in agreement with literature

Superconducting phase fluctuations in SmFeAsO0.8_{0.8}F0.2_{0.2} from diamagnetism at low magnetic field above TcT_{c}

Superconducting fluctuations (SF) in SmFeAsO$_{0.8}$F$_{0.2}$ (characterized by superconducting transition temperature $T_{c} \simeq 52.3$ K) are investigated by means of isothermal high-resolution dc magnetization measurements. The diamagnetic response to magnetic fields up to 1 T above $T_{c}$ is similar to what previously reported for underdoped cuprate superconductors and it can be justified in terms of metastable superconducting islands at non-zero order parameter lacking of long-range coherence because of strong phase fluctuations. In the high-field regime ($H \gtrsim 1.5$ T) scaling arguments predicted on the basis of the Ginzburg-Landau theory of conventional SF are found to be applicable, at variance with what observed in the low-field regime. This fact enlightens that two different phenomena are simultaneously present in the fluctuating diamagnetism, namely the phase SF of novel character and the conventional SF. High magnetic fields (1.5 T $\lesssim H \ll H_{c2}$) are found to suppress the former while leaving unaltered the latter one.Comment: 7 pages, 5 figure

Non-conventional superconducting fluctuations in Ba(Fe1-xRhx)(2)As-2 iron-based superconductors

We measured the static uniform spin susceptibility of Ba(Fe1−xRhx)2As2 iron-based superconductors, over a broad range of doping (0.041 ≤ x ≤ 0.094) and magnetic fields. At small fields (H ≤ 1 kOe) we observed, above the transition temperature Tc, the occurrence of precursor diamagnetism, which is not ascribable to the Ginzburg–Landau theory. On the contrary, our data agree with a phase fluctuation model, which has been used to interpret a similar phenomenology occurring in the high-Tc cuprate superconductors. Additionally, in the presence of strong fields, the unconventional fluctuating diamagnetism is suppressed, whereas Ginzburg–Landau fluctuations are found, in agreement with literature.This is a peer-reviewed, un-copyedited version of an article accepted for publication/published in Journal of Physics: Condensed Matter. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at DOI: 10.1088/0953-8984/26/40/405703. Posted with permission.</p

Sobre a distribuição geográfica do Meloidogyne coffeicolla Lord e Zamith no Estado do Paraná

O presente trabalho refere-se a análise de raízes de cafeeiros para verificação da presença do nematóide do cafeeiro e dá sua distribuição geográfica no Estado do Paraná. ABSTRACT This paper describes the occurence and geographical distribution of nernatodes Meloidogyne coffekolla Lord & Zamith on coffee roots in the State of Parana. RÉSUMÉ Ce travail scerne Ianalyse dos racines du caféyeur por une vérification de a présence du nématoide MeI&dogyne coffeicolla Lord e Zamith et pour évalier sa distribution géographique dans IÈtat du Paraná