Influence of lattice volume on magnetic states of Ce2Fe16MnDy compounds y 0,1,2.3

The substitution of Mn for Fe in Ce2Fe17 suppresses its ferromagnetic ground state completely for Mn contents x amp; 8805; 0.5 Mn f.u. Ce2Fe16Mn has only an antiferromagnetic phase incommensurate helix along c axis below TN 198 K. In this paper we present and discuss the effects of deuterium insertion that can be considered as application of negative chemical pressure on the magneto structural properties of Ce2Fe16Mn. Application of positive high pressures up to 10 kbar on Ce2Fe16MnDy deuterides y 1, 2.3 allowed us to estimate the role of lattice volume and to divide it from the role of modified electronic band structure that both determines the magnetic states of the deuterated compounds. The results show that a ferromagnetic phase is stabilized by the insertion of D into the antiferromagnetic Ce2Fe16Mn. The Curie temperature TC of Ce2Fe16MnDy deuterides increases with increasing D content reaching TC 258 K for y 2.3 and remarkably decreases with pressure dTC dP 5.4 K kbar and dTC dP 3.6 K kbar for Ce2Fe16MnD1 and Ce2Fe16MnD2.3, respectively. Significant difference between the magnetization of Ce2Fe16MnD1 under pressure and the one of the parent compound at ambient pressure indicates that changes of the volume alone cannot determine the magnetic states upon the initial deuteration. However, the volume expansion becomes dominant when increasing the deuterium content up to 2.3 D f.