^25Mg NMR study of the MgB_2 superconductor

M. Mali; J. Roos; A. Shengelaya; H. Keller; K. Conder

doi:10.1103/PhysRevB.65.100518

^25Mg NMR study of the MgB_2 superconductor

Superconductivity 2009-11-07 v2

Authors: M. Mali , J. Roos , A. Shengelaya , H. Keller , K. Conder

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Abstract

^25Mg NMR spectra and nuclear spin-lattice relaxation time, T_1, have been measured in polycrystalline ^25MgB_2 with a superconducting transition temperature T_c = 39.0 K in zero magnetic field. From the first order and second order quadrupole perturbed NMR spectrum a quadrupole coupling frequency nu_Q = 222(1.5) kHz is obtained. T_1T = 1090(50) sK and Knight shift K_c = 242(4) ppm are temperature independent in the normal conducting phase. The ^25Mg Korringa ratio equals to 0.95 which is very close to the ideal value of unity for s-electrons. The comparison of the experimental nu_Q, T_1T, and K_c with the corresponding values obtained by LDA calculations shows an excellent agreement for all three quantities.

Keywords

MgB2 superconductor NMR nuclear spin-lattice relaxation Knight shift quadrupole coupling Korringa ratio

Cite

@article{arxiv.cond-mat/0111022,
  title  = {^25Mg NMR study of the MgB_2 superconductor},
  author = {M. Mali and J. Roos and A. Shengelaya and H. Keller and K. Conder},
  journal= {arXiv preprint arXiv:cond-mat/0111022},
  year   = {2009}
}

Comments

4 pages including 4 eps-figures, revtex4

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