Spin-flop phase and heavy fermion behavior in CePb₃

The magnetoresistance of a high-quality single crystal of the antiferromagnetic heavy fermion compound CePb₃ has been measured as a function of field up to 18 T, as a function of temperature between 8 mK and 8 K, and as a function of field orientation. Below the Néel temperature, two field-induced phase transitions are observed, which occur at approximately 5 and 9.5 T with the field parallel to (110), but which merge into a single transition when the field is rotated to (100). The behavior is consistent with a spin-flop phase lying between the low-field antiferromagnetic phase and the high-field ferromagnetically polarized phase. Close to the spin-flop transition the T² coefficient of resistivity is enhanced, and the Fermi-liquid regime suppressed.