TENSOR PAIRS OF LANGBEINITE FAMILY OF CRYSTALS

摘要

The form of physical property tensors invariant under the point groups and their subgroups constitutes the basis for the tensorial classification of domain pairs in ferroic crystals which is given by the group theoretical classification of the corresponding physical property tensor pairs. Litvin and Litvin (1990) had tabulated this classification of tensor pairs for all 32 point groups and their subgroups and for all physical property tensors of rank 0, 1 & 2 (Abrahams). In this paper we have taken the Langbeinite family A_2~+ M_2~(2+) (so_4~(3-))_3 of crystals with A = NH_4, K Rb, Cs Ti & M = Mg, Ca, Mn, Fe, Co, Ni, Zn & Cd. And we found ferromagnetoelectric (aev~2) tensor pairs of the crystal using double coset decomposition and the results are tabulated.