Symmetry analysis of magnetic structures possible in Tb[Ni.sub.2][Si.sub.2] - Tb[Mn.sub.2][Si.sub.2] solid solutions

Tb[Ni.sub.2][Si.sub.2] - Tb[Mn.sub.2][Si.sub.2] solid solutions have been studied by neutron diffraction to reveal magnetic structures with wave vectors {[k.sub.8]} = [mu]([b.sub.1] - [b.sub.2]) + [b.sub.3]/2 = 2[pi][(1 - 2[mu])/2, (1 + 2[mu])/2,0]/a, {[k.sub.13]} = [b.sub.3]/2 = 2[pi](1/2,1/2,0)/a, and {[k.sub.14]} = 0. The method of calculation is described and the results of calculations are given for the basis functions of irreducible representations of the space group [D.sup.17.sub.4h](I4/mmm) that are used for the most rational search for a real model of the magnetic structure of these solid solutions. The compositions of the magnetic representations for each of the above-mentioned wave vectors and the possible variants of the mutual orientation of atomic magnetic moments in the crystallographic positions in which the magnetically active atoms (Tb, NI, MN) are located have been determined. Keywords: crystal structure, space group, symmetry elements of space group, irreducible representation of space group, character of the representation, magnetic structure, wave vector of magnetic structure, wave-vector star, magnetic representation, basis function of irreducible representation of space group, atomic component of basis function DOI: 10.1134/S0031918X14050135