Article

Hydrostatic Pressure Dependence of the Superconducting and Structural Properties of MgB2

11/2001;
Source: arXiv

ABSTRACT In this paper we report parallel in situ neutron powder diffraction and Tc(P) measurements versus pressure on the same MgB2 sample in a He-gas apparatus to 0.6 GPa; in addition, we present Tc(P) measurements in a helium-loaded diamond-anvil-cell to 20 GPa on the same sample. Our results are compared with those of other groups. The high precision achieved in these measurements allows a quantitative evaluation of the change in Tc as a function of the changes in structure. Our results are consistent with electron-phonon pairing in MgB2.

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    ABSTRACT: The hydrostatic pressure effect on the newly discovered superconductor MgBâ has been determined. The transition temperature T{sub c} was found to decrease linearly at a large rate of -1.6 K/GPa, in good quantitative agreement with the ensuing calculated value of -1.4 K/GPa within the BCS framework by Loa and Syassen, using the full-potential linearized augmented plane-wave method. The relative pressure coefficient d ln T{sub c}/dp for MgBâ also falls between the known values for conventional sp and d superconductors. The observation, therefore, suggests that electron-phonon interactions play a significant role in the superconductivity of the compound.
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