Singh, Dharmendra Kumar and Tiwari, Brajesh and Jha, Rajveer and Kishan, H. and Awana, V. P. S. (2014) Role of MgO impurity on the superconducting properties of MgB2. Physica C: Superconductivity and its Applications, 505. pp. 104-108. ISSN 0921-4534

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Abstract

We address the effect of MgO impurity on the superconducting properties of MgB2. The synthesis of MgB2 is very crucial because of sensitivity of Mg to oxidation which may lead to MgO as a secondary phase. Rietveld refinement was performed to determine the quantitative volume fraction of MgO in the samples synthesized by two different techniques. Both the samples were subjected to magnetization measurements under dc and a.c. applied magnetic fields and the observed results were compared as a function of temperature. Paramagnetic Meissner effect has been observed in a sample of MgB2 having more amount of MgO (with T-c = 37.1 K) whereas the pure sample MgB2 having minor quantity of MgO shows diamagnetic Meissner effect with T-c = 38.8 K. M-H measurements at 10 K reveal a slight difference in irreversibility field which is due to MgO impurity along with wide transition observed from ac magnetic susceptibility measurements. The magnetotransport measurements rho(T) using rho(N) = 90%, 50% and 10% criterion on pure sample of MgB2 has been used to determine the upper critical field whereas the sample having large quantity of MgO does not allow these measurements due to its high resistance.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/S Elsevier.
Uncontrolled Keywords:	MgB2 superconductor Structure Magnetization Magnetotransport
Subjects:	Physics
Divisions:	UNSPECIFIED
Depositing User:	Dr. Rajpal Walke
Date Deposited:	04 Nov 2015 07:43
Last Modified:	04 Nov 2015 07:43
URI:	http://npl.csircentral.net/id/eprint/1502

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