CECU2SI2 - MORE NEARLY MAGNETIC THAN UBE13

We have prepared and studied, via dc and ac susceptibility and specific heat, samples of Ce(1-x)M(x)Cu2.2Si2, with M = Y, La and Lu. All samples show an increase in the Wilson ratio, proportional-chi/gamma, with the low-temperature chi per Ce mole increasing from Lu to Y to La and Ce(1-x)La(x)Cu2.2Si2 actually having chi(1.8 K) per Ce mole larger than in pure CeCu2.2Si2 for x > 0.5. The low-temperature specific heat of CeCu2.2Si2 is enhanced by dilution by La, when normalized per Ce mole, whereas dilution by Y and Lu strongly depresses the per-Ce-mole specific heat. These two contrasting effects may be linked to a volume effect, since Y and Lu contract the CeCu2.2Si2 lattice while La expands it. The fact that dilute Ce in the expanded host lattice Ce(1-x)La(x)Cu2.2Si2 has increased chi and gamma at low temperatures argues for a nearness to magnetism (substantiated by recent work on Ce(1-x)Th(x)Cu2.2Si2) that contrasts with results for U(1-x)M(x)Be13.