Coexistence of antiferromagnetism with superconductivity in CePtIn; Microscopic phase diagram determined by In NMR and NQR

Sakai, Hironori   ; Tokunaga, Yo  ; Kambe, Shinsaku  ; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

Single crystals of the heavy-fermion antiferromagnet CePtIn with a Nel temperature () of 5.2 K at ambient pressure have been investigated by zero-field In-nuclear magnetic/quadrupole resonance (NMR/NQR) measurements as a function of applied pressure. Within the antiferromagnetic state the character of Ce's electron appears to change from localized to itinerant-like at GPa, approximately the pressure where superconductivity first emerges. With increased pressure, the superconducting transition reaches a maximum just at or slighty before antiferromagnetic order disappears, and not at the pressure GPa where the steeply decreasing Nel boundary extrapolates to zero temperature. For , the spin relaxation rate drops sharply by more than two orders of magnitude at , suggestive of a first order transition.