MAGNETISM OF DYPD2SI2 AND ERPD2SI2

Neutron diffraction and magnetometric measurements on polycrystalline samples of DyPd2Si2 and ErPd2Si2 were carried out in the temperature range from 2 to 293 K. Both compounds show tetragonal ThCr2Si2 type crystal structure and order at 2 K in a sine modulated magnetic structure with propagation vectors k = [0.609, 0, 0.155] and [0.575, 0, 0.083] respectively. The oscillatory character of magnetic order found in RPd2Si2 (R = Tb-Er) compounds suggests exchange interactions described by the RKKY model to be dominant, but the non-monotonic dependence of respective Neel temperatures on the number of f-electrons indicates the influence of a crystalline electric field (CEF) on the magnetic behaviour in this series.