Magnetic irreversibility and zero resistance in granular Y358 superconductor

F T Dias,V N Vieira,C P Oliveira,F Mesquita,D L Silva,P Pureur,M L Almeida,J Schaf

doi:10.1088/1742-6596/568/2/022009

Abstract

We report on magnetization and magnetoresistance measurements of polycrystalline Y3Ba5Cu8O18 superconductor (Y358), prepared by solid state reaction in order to study the correlation between the magnetic irreversibility line and the zero electric resistance as a function of applied field. The magnetization measurements were performed using a MPMS-XL SQUID magnetometer and the magnetoresistance measurements were made using a PPMS, both from Quantum Design, up to 1 T. The granular microstructure was confirmed by scanning electron microscopy. In this case the grain junctions are weaker than in the Y123 system and the effect of the applied field on the grain couplings is much stronger. Consequently, in our sample the zero resistance line shifts away from the irreversibility line and is lower by more than 15 K at 1 T. We explain our results in terms of the superconducting glass model and in comparison with results obtained in other materials from the YBaCuO family.

Highlights

The discovery of the new member of the YBaCuO-family, the Y 3Ba5Cu8O18 superconducting system [1], or Y3Ba5Cu8O18 superconductor (Y358), has allowed the access to new and important results about the phenomenology of the superconducting cuprates, there are some differences between the family members
The magnetization experiments were performed in a SQUID magnetometer (SQUID MPMS-XL from Quantum Design) and consisted of the standard method for measuring the magnetic irreversibility, based on zero-field-cooled (ZFC) and field-cooled (FC) procedures [17]
The method consisted in initially cooling down our sample below the critical temperature (TC) in zero magnetic field (ZFC)

Summary

Introduction

The discovery of the new member of the YBaCuO-family, the Y 3Ba5Cu8O18 superconducting system [1], or Y358, has allowed the access to new and important results about the phenomenology of the superconducting cuprates, there are some differences between the family members. In this work we have performed magnetization and magnetoresistance measurements up to 1 T in a polycrystalline Y3Ba5Cu8O18 sample to study the magnetic irreversibility line and the zero resistance state, as well as the correlation between both behaviors. Previous magnetic and electric (four probe resistivity) measurements were used to verify the superconducting state of our samples.

Results

Conclusion