Competition between the valence transition and the magnetic ordering of YbInCu4 probed by 63Cu NQR at high pressure

Abstract We have performed 63 Cu NQR measurement to investigate the pressure effect on the electronic state of YbInCu 4 . Applying pressure lowers the valence transition temperature T v and stabilizes the localized electron state. For the pressure above 2.4 GPa, in the pressure-stabilized localized electron state, 1/ T 1 shows near temperature-independent behavior and exhibits a divergent increase at 2.4 K due to the critical slowing down of magnetic moment fluctuations. These results suggest that the localized electron state of YbInCu 4 directly transforms into the magnetically ordered state without taking any intermediate heavy-Fermion or superconducting states.