Kumar, Anuj and Jha, Rajveer and Singh, Shiva Kumar and Kumar, Jagdish and Ahluwalia, P. K. and Tandon, R. P. and Awana, V. P. S. (2012) Superconductivity in the vicinity of ferromagnetism in oxygen free perovskite MgCNi3: An experimental and density functional theory study. Journal of Applied Physics , 111 (3). 033907. ISSN 0021-8979

PDF - Published Version Restricted to Registered users only Download (1450Kb) | Request a copy

Abstract

e report synthesis, structural, magnetic, specific heat, and density functional theory (DFT) studies on the MgCNi3 superconductor. Polycrystalline MgCNi3 samples are synthesized through the standard solid state reaction route and found to crystallize in the cubic perovskite structure with space group Pm3m, without any detectable trace of Ni impurity. Both AC and DC magnetization exhibited superconducting transition (T-c) at around 7.25 K. The lower critical field (H-c1) and irreversibility field (H-irr) are around 140 Oe and 11 kOe, respectively, at 2 K. The upper critical field (H-c2) being determined from in-field AC susceptibility measurements is 11.6 kOe and 91.70 kOe with 50% and 90% diamagnetism criteria, respectively. Heat capacity (C-p) measurements are carried out under an applied field of up to 140 kOe and down to 2 K. The Sommerfeld constant (gamma) and Debye temperature (Theta(D)) as determined from low temperature fitting of C-p(T) data to the Sommerfeld-Debye model are 36.13 mJ/mol K-2 and 263.13 K, respectively. The Bardeen-Cooper-Schrieffer (BCS) parameter (2 Delta/KBTc,) is around 3.62, suggesting MgCNi3 to be an intermediate coupled BCS superconductor with value lambda = 0.69. Although the DFT calculations exhibited the compound to be non-magnetic but with spin fluctuations, the experimental isothermal magnetization MH loops at 20, 50, 100, 200, and 300 K showed some ferromagnetic nature in this compound with coercive field (H-c) of around 50 Oe at 20 K. The Ni-3d states play dominant roles near the Fermi levels and there is strong hybridization between Ni-3d and C-2p states. It seems that MgCNi3 is superconducting in close proximity of ferromagnetism.

Item Type:	Article
Additional Information:	copyright for this article belongs to M/s American Institute of Physics
Subjects:	Applied Physics/Condensed Matter
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	19 Aug 2026 10:55
Last Modified:	19 Aug 2026 10:55
URI:	https://npl.csircentral.net/id/eprint/3388

Actions (login required)

View Item