DEVELOPMENT OF MAGNETIC ORDER IN CECU2(SI1-XGEX)(2) AS A FUNCTION OF HYBRIDIZATION

In the alloy system CeCu2(Si1-xGex)(2) phase A, i.e., antiferromagneti c order at x > 0, evolves from a heavy-fermion state at x = 0, where T -A --> 0 and non-Fermi-liquid effects are observed. Here, we present t he results of specific-heat measurements on a CeCu2(Si0.9Ge0.1)(2) pol ycrystal as a function of external magnetic held (0 less than or equal to B less than or equal to 8 T) and hydrostatic pressure (0 less than or equal to p less than or equal to 1 GPa). In this sample a magnetic (T-A = 1.4 K) and a superconducting (sc) phase (T-C = 0.21 K) have be en observed at p = 0. Our finite-pressure results indicate a subtle di fference between steric and chemical effects. At p = 1.0 GPa supercond uctivity sets in at T-C less than or equal to 0.55 K, while T-A remain s almost unchanged. (C) 1998 Elsevier Science B.V. All rights reserved .