Frustrated magnetic structure of TmAgGe

Physical properties of the compound TmAgGe have been investigated by means of magnetometric, transport, calorimetric as well as neutron diffraction measurements. The compound crystallizes in the hexagonal ZrNiAl-type crystal structure. The reported results indicate that the sample exhibits an antiferromagnetic ordering below TN=4.2K. The low temperature behavior of the magnetic susceptibility and the specific heat is in good agreement with the spin-wave theory with linear dispersion relation. In addition, the magnetic structure of TmAgGe was determined by means of neutron diffraction measurements. The Tm moments are equal to 6.44(10) μB at 1.5 K and form a non-collinear magnetic structure within the basal plane. To describe this structure three different propagation vectors: k→=[1/2 ,0,0], k→'=[-1/2 ,1/2 ,0] and k→''=[0,1/2 ,0] are required. Such a spin arrangement is analyzed on the basis of group theory.