Further pressure studies around the magnetic instability of CePd2Si2

Abstract

Using helium as a pressure-transmitting medium in a diamond anvil cell enabled a high-quality sample of the antiferromagnet CePd₂Si₂ to be studied in a highly hydrostatic environment. With the aid of a low-temperature force-modulation device, ac calorimetric measurements were made up to 25 kbar and resistivity measurements up to 33 kbar, on both sides of P_C, found between 28 and 29.5 kbar. The narrow superconducting domain found around P_C indicates the connection between the magnetic instability and the formation of Cooper pairs. We assert that there is an influence of the residual resistivity both on the emergence of superconductivity, and on the corresponding transition width. Close to P_C, the temperature dependence of the resistivity in the normal state qualitatively agrees with the spin-fluctuation model. While standard Fermi liquid behaviour was found to break down in the immediate vicinity of P_C, it reappeared below 700 mK at 33 kbar, less than 5 kbar above.