Magnetic and Crystallographic Structure of Y₆Mn₂₃D₂₃

Abstract

The magnetic behavior of Y6Mn23 is dramatically altered upon hydrogenation (or deuteration). In this study it has been found, by means of high-resolution powder diffraction and Rietveld refinement techniques, that the crystallographic structure is distorted from face-centered cubic (Fm3m) at 295 K to a primitive tetragonal structure at 4 K in which deuterium atoms are atomically ordered. Y6Mn23 is a ferromagnetic compound with Tc=486 K, and bulk magnetization of 13.2 Bf.u. (formula unit). After deuteration of Y6Mn23 to the composition Y6Mn23D23, low-temperature scattering data (T\u3c180 K) show that the b and f2 sites in the Fm3m structure are antiferromagnetic and the d and f1 sites have no spontaneous magnetic moment. © 1984 The American Physical Society