OBSERVATION OF INDEPENDENT IRON AND RARE-EARTH ORDERING IN RFE6GE6 (R=Y, GD-LU) COMPOUNDS

Mossbauer and magnetization measurements have been used to study magnetic ordering in RFe6Ge6 alloys. The iron sublattice orders antiferromagnetically and TN remains essentially constant across the series at ∼480 K with no evidence of a net magnetization in any of the alloys. For R=Gd−Er, the rare‐earth sublattice orders ferromagnetically with Tc’s that descend from 30 K at Gd to 3 K at Er. This order is established without affecting the order on the iron sublattice. The large difference in ordering temperatures and the unrelated magnetic structures adopted by the two sublattices indicate that the iron and rare‐earth moments are effectively isolated from each other and that they order independently.