PRESSURE-INDUCED LOCAL MOMENT MAGNETISM IN THE NONMAGNETIC HEAVY-FERMION COMPOUND YB2NI2AL

High pressure measurements on the nonmagnetic (NM) heavy fermion (HF) compound Yb2Ni2Al using the Yb-170 Mossbauer effect, electrical resist ance, and x-ray diffraction techniques reveal for p > 8 GPa and below 2 K a crossover from the NM HF state to a magnetically ordered state o f Yb(4f) local moments (mu(Yb) approximate to 1 mu g at 1.8 K and 9 GP a). This crossover is not connected with a change of the Yb valence st ate. In the magnetic regime, we find a coexistence of discrete magneti c and nonmagnetic phases characteristic of a first order phase transit ion. [S0031-9007(98)07790-4].