Study on crystalline field effects in PrAl3 by neutron inelastic scattering technique

In the present work, the effects produced by the crystalline electrical field (CEF) in PrAl3 have been investigated. In the compound studied, a Pr3+ ion is found in an electrical field of the hexagonal symmetry, which separates the main multiplet of the ion into a number of sublevels. The doubly differential cross section for slow neutron scattering by polycrystalline samples of LaAl3 and PrAl3 has been measured. The experiments have been conducted using a time-of-flight spectrometer, with the incident neutron energy E0=4.75 MeV and at sample temperatures of 100 deg K and 295 deg K. In the spectrum of PrAl3 several intensive peaks have been discovered caused by the effects associated with the separation of the ground state of the Pr3+ ion by the crystalline electric field (CEF). The complete separation occurs at a temperature of not less than 130 deg K. The separated level scheme has been restored and the parameters of the CEF Hamiltonian have been obtained. The temperature dependence of the Schottky heat capacity has been calculated according to the separated level scheme. The calculated curve is compared with that obtained experimentally