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Abstract

A new phase of ErMn2D6 has been prepared by applying high hydrogen
pressure on C14 ErMn2. This phase is isostructural to YMn2D6 and
crystallizes with a K2PtCl6 type structure having an ordered anion and
a partially disordered cation arrangement as Er and half the Mn atoms
are randomly substituted in the same 8c site. This hydride is very
stable and decomposes into ErD2 and Mn at about 630 K. The reverse
susceptibility follows a Curie - Weiss law with an effective moment of
10 mu(B) similar to that of ErMn2. Although a saturation magnetization
of 5 mu(B) is measured at 4.2 K, smaller than that of ErMn2 (8 mu(B)),
no long range magnetic order is observed in the neutron patterns. Short
range magnetic order, corresponding to both ferromagnetic and
antiferromagnetic correlations, is observed in the neutron patterns up
to 5 K. The chemical disorder of Er and Mn atoms on the 8c site should
prevent the long range magnetic order and favour a distribution of Er
spin orientation.