Van Vleck-Like Electronuclear Susceptibility ofYb171in Au at Very Low Temperature

Abstract
We describe superconducting-quantum-interference-device susceptibility measurements on several dilute natural and monoisotopic AuYb alloys down to 7 mK. Whereas AuYb174 obeys a Curie law in the whole range of temperature, a very unusual case of a Van Vleck-like behavior due to an electronuclear singlet ground state is reported for AuYb171.