Pressure-induced superconductivity in EuFe2As2 without a quantum critical point: magnetotransport and upper critical field measurements under high pressure

Abstract

Resistivity and Hall effect measurements of EuFe${}_2$As${}_2$ up to 3.2\,GPa indicate no divergence of quasiparticle effective mass at the pressure $P_{\mathrm{c}}$ where the magnetic and structural transition disappears. This is corroborated by analysis of the temperature ($T$) dependence of the upper critical field. $T$-linear resistivity is observed at pressures slightly above $P_{\mathrm{c}}$. The scattering rates for both electrons and holes are shown to be approximately $T$-linear. When a field is applied, a $T^2$ dependence is recovered, indicating that the origin of the $T$-linear dependence is spin fluctuations.

7 pages, 8 figures, to appear in Phys. Rev. B