Characterization, electrical transport and magnetic properties of the rare earth misfit layer compounds (TbS)(1.21)NbS2, (TbS)(1.20)TaS2, (DyS)(1.22)NbS2 and (DyS)(1.21)TaS2

X-ray powder and single-crystal X-ray diffraction of the title compounds showed that they are planar intergrowth compounds, built of alternating sandwiches TS2 (T=Nb, Ta) and double layers LnS (Ln=Tb, Dy), present in three orientational variants related by rotations of 120 degrees around the c axis perpendicular to the layers. The TS2 and LnS subsystems are incommensurate along one of the in-plane axes. The LnS subsystem in each domain is face-centered orthorhombic. The stacking of the TS2 sandwiches shows disorder and the stacking type C or F could not be elucidated. The structures of the TbS subsystem and the common projection (TbS)(1.21)TaS2 were determined using single-crystal X-ray diffraction. The Tb-S distances are in agreement with trivalent Tb. The resistivity, Hall effect and thermopower measured for crystals and compacts point to conduction in an almost filled d(Z)2 band of the NbS2 and TaS2 sandwiches corresponding to an electron donation of about 0.85 electron per T atom from LnS to TS2. Magnetic susceptibilities, measured in the range 4-300 K, are Curie-Weiss with effective magnetic moments close to those for free Ln(3+) ions. The Curie temperatures are close to zero.