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Dependence of the superconducting transition temperature of single- and polycrystalline MgB2 on hydrostatic pressure

S. Deemyad·T. Tomita·J. J. Hamlin·B. R. Beckett·J. S. Schilling·D. G. Hinks·J. D. Jorgensen·S. Lee·S. Tajima
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Abstract

The dependence of Tc for MgB2 on purely hydrostatic or nearly hydrostatic pressure has been determined to 23 GPa for single-crystalline and to 32 GPa for polycrystalline samples, and found to be in good agreement. Tc decreases from 39 K at ambient pressure to 15 K at 32 GPa with an initial slope dTc/dP = -1.11(2) K/GPa. Evidence is presented that the differing values of dTc/dP reported in the literature result primarily from shear-stress effects in nonhydrostatic pressure media and not differences in the samples. Although comparison of these results with theory supports phonon-mediated superconductivity, a critical test of theory must await volume-dependent calculations based on the solution of the anisotropic Eliashberg equations.

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S. Deemyad, T. Tomita, J. J. Hamlin, B. R. Beckett, J. S. Schilling, D. G. Hinks, J. D. Jorgensen, S. Lee, S. Tajima. 2002-09-11. Dependence of the superconducting transition temperature of single- and polycrystalline MgB2 on hydrostatic pressure. https://doi.org/10.1016/s0921-4534(02)02300-6

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