Abstrakt
(Ce,La)Pd2(Al,Ga)2 are intermetallic compounds with a tetragonal CaBe2Ge2 structure type at room temperature. This structural type is very common in intermetallic com- pounds with a 1:2:2 stoichiometry.
The studied compounds undergo a structural phase transition at low temperatures. The low temperature structure of CePd2Al2 is orthorhombic (Cmme) below 13.5 K [1] and CePd2Ga2 is triclinic below 125 K [2].
Similar structural behaviour is observed in their non-magnetic La analogues. lt is not known what causes the different behaviour of CePd2Al2 and CePd2Ga2 com- pounds at low temperatures considering the room tempera- ture structure is similar for both compounds. The CePd2Al2 is also one of the rare examples of Ce-based compounds whose magnetic excitations in crystal electric field does not fulfil the scheme based on a tetragonal point symmetry of the Ce ion [1].