Metamagnetic transitions in Y0.5Er0.5Fe2D4.2 deuteride studied by high magnetic field and neutron diffraction experiments

Abstract

The structural and magnetic properties of Y 0.5 Er 0.5 Fe 2 D 4.2 deuteride have been investigated by continuous high field magnetic measurements up to 35 T and neutron powder diffraction experiments versus temperature and applied field. Y 0.5 Er 0.5 Fe 2 D 4.2 crystallizes in a monoclinic structure (Pc space group) resulting from the deu-terium order into 18 interstitial tetrahedral sites. At low field, the deuteride is ferrimagnetic (Ferri) up to 38 K, between 38 and 50 K, it undergoes a first order transition towards an antiferromagnetic (AFM) structure, which remains present up to T N = 115 K. Upon applied field, two different types of metamagnetic behavior are observed depending on the temperature range. Below 38 K, a forced ferrimagnetic-ferromagnetic (FM) transition is observed at a transition field B Trans of only 7 T (at 2 K), which is among the smallest encountered for Fe rich intermetallics. B Trans is not very sensitive to temperature changes nor to the Er content and its moderate value is explained by a deuterium induced weakening of the Er-Fe interaction. The second metamagnetic transition, observed between 38 and 150 K, from an AFM (Para) towards a FM structure, is related to the itinerant electron metamagnetic behavior of the Fe sublattice. B Trans increases linearly versus temperature with a dB/dT slope of 0.24 ± 0.01 T.K −1. Above B Trans , Er moments parallel to the Fe moments are induced.