Magnetic structure and crystal field in cerium compounds with CsCl-type structure

Neutron diffraction and spectroscopy experiments have been performed on the cubic (CsCl-type structure) compounds CeAg, CeZn and CeMg. CeAg orders ferromagnetically with a moment μsub(F)=0.8μsub(B) at 1.7 K. CeZn and CeMg are antiferromagnets; at 4.2 K their magnetic moments are 1.95 μsub(B)(CeZn) and 1.85μsub(B)(CeMg). In the ordered state, they reveal a strong quadratic distortion, the (c/a-1) value reaching 1.9% in CeAg at 1.7 K; in CeAg additional atoms shifts seem to be present in the tetragonal cell. Crystal field parameters have been determined as A4(r4)= 117 K (CeAg), 74 K (CeZn) and 117 K (CeMg); the consistence of the results with all the previous studies is discussed. (Auth.)