Pressure effects on the Tc of superconducting MgCxNi3

Abstract

The effect of hydrostatic pressure (P) up to 17 kbar on the superconducting transition temperature (Tc) of the newly discovered intermetallic non-oxide perovskite superconductor MgCxNi3 has been reported. The TC is found to increase with increasing P at a rate of dTc/dP ~ 0.0134 to 0.0155 K/kbar depending on the value of carbon content x. The absolute value of dTc/dP for MgCxNi3 is about the same as that of intermetallic RNi2B2C (R = rare earths) and metallic superconductors but about one order of magnitude smaller than that of the most recently and intensively studied superconductor MgB2. However, the dlnTc/dP ~ 0.00181 to 0.00224 kbar-1 and the rate of change of Tc with unit cell volume (V), dlnTC/dlnV ~ -3.18 to -2.58 of MgCxNi3 are having the comparable magnitude to that of MgB2 with opposite sign. The increase of Tc with P in MgCxNi3 can be explained in the frame work of density of states (DOS) effect.