Polarized-neutron study of the magnetic-polaron state in CeP

The Ce magnetic form factor in different magnetic phases of CeP has been st udied by unpolarized and polarized neutron diffraction. In the type-I antif erromagnetic phase (H = 0, T = 2 K), the form factor agrees with the calcul ation for a Gamma(7) crystal-field ground state. On the other hand, the res ults for H = 3 T and T = 1.7 K (in so-called "phase I") indicate that the C e ions with large moments occurring in the structure are in a strongly pola rized state very close to the crystal-held state Gamma(8). This result supp orts the view that a Gamma(8)-like wave-function is stabilized at ordered C e sites by the formation of a magnetic-polaron state. (C) 1999 Elsevier Sci ence B.V. All rights reserved.