Resonant X-ray scattering on antiferroquadrupolar ordering compound Dy 0.8Gd 0.2B 2C 2

Abstract

Gd substitution in DyB 2C 2 enhances the antiferromagnetic (AFM) interaction and weakens the antiferroquadrupolar (AFQ) interaction. In Dy 0.8Gd 0.2B 2C 2, two successive transitions occur. By performing resonant X-ray scattering measurements, we confirmed the AFQ ordering temperature T Q = 18.0 K and the Néel temperature T N = 19.5 K ; T N is higher than T Q in Dy 0.8Gd 0.2B 2C 2, in contrast to DyB 2C 2. There exists an AFM phase between T Q and T N , and the magnetic structure is described by k = [ 1 0 0 ] . This kind of AFM phase is also observed in HoB 2C 2 and TbB 2C 2, although the magnetic structures of these compounds are long-periodic ones.