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Pinning force data, Fp, of a variety of Fe-based high-Tc superconductors (11-, 111-, 122- and 1111-type) were analyzed by means of a scaling approach based on own experimental data and an extensive collection of literature data. The literature data were mostly replotted, but also converted from critical current measurements together with data for the irreversibility line when available from the same authors. Using the scaling approaches of Dew-Hughes and Kramer, we determined the scaling behavior and the best fits to the theory. The data of most experiments analyzed show a good scaling behavior at high temperatures when plotting the normalized pinning force Fp/Fp,max versus the irreversibility field, Hirr. The resulting peak positions, h0, were found at 0.3 for the 11-type materials, at 0.48 for the 111-type materials, between 0.32 and 0.5 for the 1111-type materials and between 0.25 and 0.71 for the 122-type materials. This high peak position ensures a good performance of the materials in high applied magnetic fields and is, therefore, a very promising result concerning the possible applications of the Fe-based high-Tc superconductors.
Motivated by the recent experiment of the non-BCS scaling relation of the condensation energy $Delta CE$ vs. $T_c$ ($Delta CE sim T_c ^{beta}, betaapprox 3.5$) [PRB 89 140503 (2014)] for the Fe-based superconductors, we studied the CE and $T_c$ of th
We review neutron scattering investigations of the crystal structures, magnetic structures, and spin dynamics of the iron-based RFe(As,P)O (R=La, Ce, Pr, Nd), (Ba,Sr,Ca)Fe2As2, and Fe1+x(Te-Se) systems. On cooling from room temperature all the undope
We report on successful synthesis under high pressure of a series of polycrystalline GdFeAs O_{1-x}F_x high-Tc superconductors with different oxygen deficiency x=0.12 - 0.16 and also with no fluorine. We have found that the high-pressure synthesis te
A quarter of a century after their discovery the mechanism that pairs carriers in the cuprate high-Tc superconductors (HTS) still remains uncertain. Despite this the general consensus is that it is probably magnetic in origin [1] so that the energy s
The recent observation of quantum oscillations in underdoped high-Tc superconductors, combined with their negative Hall coefficient at low temperature, reveals that the Fermi surface of hole-doped cuprates includes a small electron pocket. This stron