Abstract：CrO2-TiO2 composites are synthesized by using a high temperature and high pressure method using CrO3 and H2TiO3 as precursors. The composites consist of large rod-like CrO2 crystals separated by small TiO2 grains. The CrO2 in the composites is very pure and its saturation magnetization is very close to the theoretical value (i.e., 2μB per formula unit). The composites exhibit a large negative magnetoresistance (MR) at 5 K. The MR in CrO2-TiO2 composites is mainly attributed to spin-polarized tunneling between CrO2 crystals. The conductivity of the composites is best described by a fluctuation-induced tunneling model below 230 K.
2013, Vol. 30 
