Structural and magnetic properties of RMn2−xFexD6 compounds (R=Y, Er; x≤0.2) synthesized under high deuterium pressure

RMn2−xFexD6 compounds were obtained by applying a deuterium pressure of several kbar to RMn2−xFex compounds for x≤0.2 and R=Y, Er. These compounds are isostructural to RMn2D6 compounds and crystallize in a K2PtCl6 type structure with a random substitution of R and half the Mn atoms in the same 8c site whereas the other Mn atoms are located on the 4a site and surrounded by six D atoms (24e site). According to neutron powder diffraction analysis the Fe atoms are preferentially substituted on the 4a site. YMn2−xFexD6 compounds are paramagnetic and their molar susceptibility follows a modified Curie–Weiss law. ErMn2−xFexD6 compounds display a ferromagnetic behavior at 2 K, but their saturation magnetization (MS∼4.0 μB/f.u.) is half that of their parent compounds (MS∼8.0 μB/f.u.). The neutron diffraction patterns of ErMn1.8Fe0.2D6 display below 13 K both ferromagnetic and antiferromagnetic short range order, which can be related to a disordered distribution of Er moments. The paramagnetic temperatures of ErMn2−xFexD6 compounds are negative and decrease versus the Fe content whereas they are positive and increase for their parent compounds.

Neutron powder diffraction (NPD) patterns of ErMn1.8Fe0.2D6 at 1.4 and 30 K measured on G4.1 spectrometer. Inset: difference curves between the NPD patterns measured at T1 and 30 K showing ferromagnetic (FM) and antiferromagnetic (AFM) short range order.Figure optionsDownload as PowerPoint slideResearch highlights
► RMn2−xFex compounds (x≤0.2) were synthesized under 10 kb deuterium pressure.
► The Fe atoms are substituted to Mn on 4a site.
► RMn2−xFexD6 desorb D up to 1115 K forming the parent intermetallics by recombination.
► ErMn2−xFexD6 compounds show coexistence of ferro- and antiferromagnetic SRO below 10 K.