Four-point electrical resistivity measurements were carried out on Nd metal and dilute magnetic alloys containing up to 1 at.% Nd in superconducting Y for temperatures 1.5-295 K under pressures to 210 GPa. The magnetic ordering temperature To of Nd appears to rise steeply under pressure, increasing ninefold to 180 K at 70 GPa before falling rapidly. Y(Nd) alloys display both a resistivity minimum and superconducting pair breaking ΔTc as large as 38 K/at.% Nd. The present results give evidence that for pressures above 30-40 GPa, the exchange coupling J between Nd ions and conduction electrons becomes negative, thus activating Kondo physics in this highly correlated electron system. The rise and fall of To and ΔTc with pressure can be accounted for in terms of an increase in the Kondo temperature.
