Resonant X-ray diffraction study of multipole ordering in the ferromagnetic compound CePdS

Michimura, Shinji*; Inami, Toshiya; Matsuoka, Eiichi*; Watahiki, Masanori*; Tanigaki, Katsumi*; Onodera, Hideya*

Resonant X-ray diffraction experiments on CePdS were performed at the Ce- absorption edge to study the states of quadrupolar ordering below the ferromagnetic transition temperature = 6.3 K. The magnetic structure of CePdS was reported as a canted ferromagnetic structure with a canting angle of 51. It has therefore been pointed out that the complex magnetic structure arises from the simultaneous ordering of quadrupole moments. We observed the azimuthal angle dependence of the diffraction intensity of the two forbidden reflections 003 and 104 reflections for both -' and -' scattering processes. The results revealed that -type antiferroquadrupolar ordering coexists with magnetic ordering. We infer that the magnetic structure of CePdS is not a canted structure but a ferrimagnetic structure and that the quadrupole moment is also a primary-order parameter.