The magnetic properties of EuLiH3

The bulk magnetic properties of the cubic perovskite material, EuLiH3, have been investigated and the results strongly suggest that it is a ferromagnet with Tc = 38°K and θc = +40°K. Thus EuLiH3 is very likely a new semiconducting ferromagnet. The properties of EuLiH3 are compared with those of EuTiO3, also a cubic perovskite with a very similar lattice parameter (3·79 Å for EuLiH3 and 3·90 Å for EuTiO3) which is, however, antiferromagnetic below 5°K. This somewhat surprising difference is discussed in terms of the molecular field theory and the results of previous work on exchange interactions in divalent europium compounds especially the europous monochalcogenides and europium titanate as well. It is concluded that the major factor influencing the different magnetic behavior of EuLiH3 and EuTiO3 is the apparent absence of a negative near-neighbor interaction in the former which is prominent in the latter. It is suggested that this diminution of antiferromagnetic exchange in EuLiH3 is due to the inability of H− with electron configuration 1s2 to participate in super-exchange interactions to the same degree as O2− with electron configuration (He)2s2 2p6.