Pressure evolution of the magnetic field induced ferromagnetic fluctuation through the pseudo-metamagnetism of CeRuSi

Aoki, Dai*; Paulsen, C.*; Matsuda, Tatsuma; Malone, L.*; Knebel, G.*; Haen, P.*; Lejay, P.*; Settai, Rikio*; Onuki, Yoshichika; Flouquet, J.*

Resistivity measurements performed under pressure in the paramagnetic ground state of CeRuSi are reported. They demonstrate that the relative change of effective mass through the pseudo metamagnetic transition is invariant under pressure. The results are compared with the first order metamagnetic transition due to the antiferromagnetism of CeLaRuSi which corresponds to the "negative" pressure of CeRuSi by volume expansion. Finally, we describe the link between the spin-depairing of quasiparticles on CeRuSi and that of Cooper pairs on the unconventional heavy fermion superconductor CeCoIn.