Title: Study of fluctuation induced conductivity on nano diamond doped bulk MgB₂ superconductor

Authors: Intikhab A. Ansari, M. Shahabuddin, M. Husain, Arpita Vajpayee, V.P.S. Awana, H. Kishan

Addresses: Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh-11451, Kingdom of Saudi Arabia. ' Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh-11451, Kingdom of Saudi Arabia. ' Department of Physics, Jamia Millia Islamia (Central University), New Delhi 110025, India. ' National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012, India. ' National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012, India. ' National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012, India

Abstract: Carbon doped materials play a vital role in modern solid-state electronics. Carbon can crystallise in the form of diamond and graphite due to the very versatile nature. The fluctuation effect of nano diamond (ND) on bulk MgB₂ system has been studied. The resistive transition broadening of all the employed samples decreases as the magnetic field increases. The result shows the temperature derivative of resistivity, dp/dT under the different magnetic field 0T ≤ H ≤ 8T of bulk ND-doped MgB₂ system. The fluctuation induced conductivity (FIC) for different ND doped MgB₂ samples are discussed under different magnetic fields 0T ≤ H ≤ 8T. The coherence length, ζ_c(0) for all possible cases in zero fields have been estimated and plotted. In this paper, we report the study of FIC of ND doped bulk MgB₂ system in presence of magnetic field 0T ≤ H ≤ 8T. Result shows the decrease of transition temperature as we increase the magnetic field in all doped samples. The temperature derivative of resistivity, dp/dT is also discussed in different magnetic field and different doping concentration. The results show variation of FIC in Δσ vs ε⁻¹ plot in different ND doped MgB₂ samples under the range of 0T ≤ H ≤ 8T. The calculated coherence length, ζ_c(0), slightly decreases when we increase the doping concentration for ND doped MgB₂ system at zero field.

Keywords: flux pinning; transition temperature variations; fluctuations; conductivity; nano diamond doped superconductors; bulk magnesium diboride; MgB2; magnetic fields; doping concentration; nanomaterials; nanotechnology.

DOI: 10.1504/IJNBM.2009.027718

International Journal of Nano and Biomaterials, 2009 Vol.2 No.1/2/3/4/5, pp.240 - 248

Published online: 08 Aug 2009 *

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