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.

This work was partially supported by Spanish CICYTMAT2005-06806-C04-04 grant. M. A. L.-M. acknowledges a FPI grant from spanish MEC. The synchrotron radiation experiments were performed at SPring-8 (Proposal No. 2002A0153-NS2-np).

12 pages, 8 figures, 3 tables.-- PACS number(s): 61.10.Ht, 76.80. y, 71.20.Lp, 75.50.Bb

Peer reviewed