Structural study of quasi-one-dimensional vanadium pyroxene LiVSi2O6 single crystals

Single crystals of quasi-one-dimensional vanadium pyroxene LiVSi2O6 were synthesized and the crystal structures at 293K and 113K were studied using X-ray diffraction experiments. We found a structural phase transition from the room-temperature crystal structure with space group C2/c to a low-temperature structure with space group P21/c, resulting from a rotational displacement of SiO4 tetrahedra. The temperature dependence of magnetic susceptibility shows a broad maximum around 116K, suggesting an opening of the Haldane gap expected for one-dimensional antiferromagnets with S=1. However, an antiferromagnetic long-range order was developed below 24K, probably caused by a weak inter-chain magnetic coupling in the compound.