57Fe Mössbauer and x-ray magnetic circular dichroism study of magnetic compensation of the rare-earth sublattice in Nd2−xHoxFe14B compounds

Abstract

We present here a study of the magnetic properties of the Nd2−xHoxFe14B series. The macroscopic properties of these compounds evolve continuously from those of Nd2Fe14B to those of Ho2Fe14B as Ho gradually replaces Nd. The system shows a compensation of the rare-earth sublattice magnetization for a critical concentration, xc=0.55, that is reflected into the anomalous behavior of both macroscopic and microscopic magnetic probes. The combined analysis of magnetization, 57Fe Mössbauer spectroscopy and Fe K-edge x-ray magnetic circular dichroism (XMCD) measurements suggests that the origin of the anomalous magnetic behavior found at xc=0.55 is mainly due to the Ho sublattice. Moreover, the analysis of the Fe K-edge XMCD signals reveal the presence of a rare-earth contribution, reflecting the coupling of the rare-earth and Fe magnetic moments, which can lead to the possibility of disentangling the magnetic behavior of both Fe and R atoms using a single absorption edge.