Effects of slight La- or Y-doping on the magnetic properties of CeP

Effects of slight La- or Y-doping on the magnetic properties, especially an unusual magnetic phase diagram, of CeP have been studied mainly through sp ecific heat measurements under magnetic fields up to 10 T on (Ce0.90La0.10) P and (Ce0.95Y0.05)P. In spite of essentially similar behavior in the param agnetic phase, a large difference has been observed in the magnetic phase d iagram between (Ce0.90La0.10)P and (Ce0.95Y0.05)P. The phases suggesting th e existence of Gamma(8) layers similar to those of CeP are identified for ( Ce0.95Y0.05)P, but not for (Ce0.90La0.10)P. (C) 1999 Elsevier Science B.V. All rights reserved.