Inelastic Neutron scattering study of Crystal Field Effect in CeAgAl3 and PrAgAl3

Kondo lattice systems CeCuAl3 and Ag-doped CeCu1-xAgxAl3 (x  0.3) present clear evidence for rare phenomenon of magnetoelastic coupling of crystal electric field (CEF) excitations and lattice vibrons. This motivated us to investigate the spin dynamics and CEF excitations in the end point compound CeAgAl3 which should help us understand the origin of magnetoelastic coupling in CeCu1-xAgxAl3 (0  x  0.3). CeAgAl3 forms in orthorhombic Cmcm structure which admits Ag/Al site-mixing. It has ferromagnetically ordered ground state below 3.8 K, but the short range magnetic correlations develop below 15 K. PrAgAl3 which also forms in orthorhombic Cmcm structure orders ferromagnetically below 5.5 K. We performed MERLIN express measurements on CeAgAl3 [RB2490017] and obtained interesting CEF excitations, but statistics is not enough for the publication. Further investigations of RAgAl3 (R=Ce and Pr) using the inelastic neutron scattering experiment are highly desired to determine the crystal field states of these compounds in order to understand the effect of single ion anisotropy. We propose to carry inelastic neutron scattering measurements on CeAgAl3 and PrAgAl3 using MARI spectrometer to determine the crystal field level scheme.