Crystal structure and magnetic properties of titanium-based CuTi2−xMxS4 and CuCr2−xTixSe4 chalcospinels

• Chalcogenides belong to the family of compounds spinel-type.
• Resolved single crystals of the solid solutions have space group Fd-3m.
• The distortion of the tetrahedral and octahedral volume were calculated.
• These solid solutions shows a ferromagnetic or spin-glass behavior.

CuTi2−xMxS4 (M=Fe, Mn, Co; x=0.3, 0.5) and CuCr2−xTixSe4 (x  =0.3, 0.5, 0.7) chalcospinels were synthesized by conventional solid-state reactions. Their crystal structures were determined by single-crystal X-ray diffraction. All of the phases crystallized in cubic spinel-type structures (space group, Fd3¯m). For all of the chalcospinel compounds, the edge-length distortion parameter (ELD) indicated that the most distorted polyhedron was Q[(Ti,M)3Cu], which displayed an ~8% distortion from an ideal tetrahedron structure (Q=S or Se).The Mn-based thiospinel CuMn0.3Ti1.7S4 is paramagnetic, whereas the Fe-based thiospinels (CuTi2−xFexS4; x=0.3 and 0.7) are strongly antiferromagnetic due to their spin-glass states. The magnetic susceptibility measurements indicated ferromagnetic behavior for the selenospinels (CuCr2−xTixSe4; x=0.3, 0.5 and 0.7).

View along [1 0 0] of CuCr2−xTixSe4 crystal structure showing tetrahedral and octahedral units. To the right, experimental X-ray powder diffraction pattern of CuCr1.7Ti0.3Se4 (top) in compared (in a like-mirror representation) to a simulated X-ray pattern from single-crystal data (bottom).Figure optionsDownload as PowerPoint slide