X-Ray Magnetic Circular Dichroism Studies on CeNi₄B

Abstract

The CeNi 4 B compound is a mixed-valence system. It is a paramagnet with µ eff = 0.52 µ B /f.u. and the paramagnetic Curie temperature θ = −10.7 K. In the present research we complete our previous magnetic susceptibility and X-ray photoemission measurements with new studies by the X-ray magnetic circular dichroism method. The observation of the Ce M 4,5 edges carried out with X-ray magnetic circular dichroism confirms the mixed-valence state deduced previously from X-ray photoemission spectroscopy. Moreover, we report on the measurements of the Ni L 2,3 edges, which enable verification of the Ni contribution to the magnetism of this compound.

Magnetocaloric effect in the ferromagnetic GdNi4M (M=Al, Si) and antiferromagnetic NdNiAl4 compounds

“…Hence, the most plausible explanation of the Arrott plots appears after recalling that a small magnetic moment exists on the Ni atoms, which is antiparallel to the rare earth moment. It was observed for the parent compound GdNi 5 [3] but we found it also for ternary RNi 4 M compounds by electronic structure calculations and X-ray magnetic circular dichroism (XMCD) measurements [16,13,17]. Therefore, the slope change of the Arrott plots can be ascribed to a field-induced first order type AFM-FM transition.…”