Pinning force scaling analysis of Fe-based high-Tc superconductors

Abstract

Pinning force data, [Formula: see text], of a variety of Fe-based high-[Formula: see text] 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 [J. Appl. Phys. 44, 1360 (1973)] and Kramer [Philos. Mag. 30, 293 (1974)], 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 [Formula: see text] versus the irreversibility field, [Formula: see text]. The resulting peak positions, [Formula: see text], were found at [Formula: see text] for the 11-type materials, at [Formula: see text] 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. Compared to the typical results of Bi2Sr2CaCu2O[Formula: see text] [Formula: see text] and YBa2Cu3O[Formula: see text] [Formula: see text], most of the 122 and 1111 samples investigated show peak values higher than 0.4, which is similar to the data obtained on the light-rare earth 123-type HTSC like NdBa2Cu3Oy. 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-[Formula: see text] superconductors.