Crystal Growth of MoO2 and Kx MoO 2-δ

During the last years our group has searched for new quasi-one- dimensional (1D) conductors, which led to the discovery of K_x Mo O_{2 - δ} . The electrical resistivity of this compound is well described by a power law in temperature. In this presentation, progress on the crystal growth of K_x Mo O_{2 - δ} will be discussed. Crystal growth of the parent compound Mo O₂ utilizes chemical vapor transport (CVT) with iodine as transport agent. Crystal growth of K_x Mo O_{2 - δ} by CVT was carried out using high purity K₂ Mo O₄ , Mo O₃ , and Mo powders which were mixed in appropriate amounts (0 <= x <= 0.25) and sealed with I₂ in quartz tubes, followed by heat treatment in temperature gradients from 750 to 950^o C for 100 h. The crystals were characterized by X-ray diffraction, scanning electron microscope (SEM), Raman spectroscopy, electrical resistance and magnetization measurements.

This material is based upon support by FAPESP (2008/10574-6, 2009/14524-6, and 2010/06637-2) and CNPq (301334/2007-2, 490182/2009-7).