Carbon nanofibers addition on transport and superconducting properties of bulk YBa2Cu3O7\u2212\u03b4 material prepared via co-precipitation

Nur Atikah Baharuddin,Azhan Hashim,Lim Kean Pah,Nurul Auni Khalid,Mohd Mustafa Awang Kechik,Chen Soo Kien,Zainal Abidin Talib,Abdul Halim Shaari,Masato Murakami,Hussein Baqiah,Muralidhar Miryala

doi:10.1007/s10854-020-04255-0

Abstract

The effects of carbon nanofibers addition on transport and superconducting properties of YBa2Cu3O7−δ (Y-123) superconductor were studied. Y-123 was prepared using co-precipitation method for good quality bulk of high temperature superconducting material. Carbon nanofibers with 0.2–0.8 wt% were added into Y-123 superconductors. The samples were characterized using electrical resistance measurement for critical temperature (Tc) and critical current density (Jc), powder X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis. Most of the samples indicated a dominant Y-123 phase of an orthorhombic structure with a minor phase of BaCO3 and Y-124. Onset critical temperature was found to decrease from 90.5 to 80 K with increasing of carbon nanofibers concentration. The Jc for pure sample is 11 A/cm2 at 30 K while the Jc of sample with 0.4 wt% carbon nanofibers is 830 A/cm2 at 30 K. Introduction of carbon nanofibers enhanced Jc significantly. However, further addition of carbon nanofibers in Y-123 superconductor caused degradation in Jc.

Highlights

A revolutionary discovery of YBCO or Y-123 with chemical formula of YBa2Cu3O7-d was the first ever material discovered to show Tc above the boiling point of liquid nitrogen (77 K) [1, 2]
Following up the same motivation, the aim of this work is to investigate the impact of carbon nanofibers (CNFs) on the structural and transport properties of YBCO and compared it with those obtained via CNTs addition
The addition of CNFs changed the metallic behavior of normal state in the pure sample to semiconducting behavior in the samples of x = 0.2–0.8 wt%

Summary

Introduction

A revolutionary discovery of YBCO or Y-123 with chemical formula of YBa2Cu3O7-d was the first ever material discovered to show Tc above the boiling point of liquid nitrogen (77 K) [1, 2]. This means that superconductors would no longer require a complex cooling system for their applications unlike other materials that rely on liquid helium for their operation which is rather costly. The material has been recognized as second generation high temperature superconductors (HTS) and gave huge impacts to the market penetration for technology and power applications [3]. The weak flux pinning and granularity of Y-123 especially at temperatures above 20–30 K seems to limit the value of Jc [4].

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Results

Conclusion