Colossal magnetoresistance in La1−xLixMnO3

La 1−x Li x MnO 3 (x=0, 0.1, 0.2, and 0.3) were synthesized by using conventional solid state reaction and partial melting technique. The compounds were determined to be of rhombohedral structure by x-ray powder diffraction. For the x=0.2 and x=0.3 samples, room temperature neutron powder diffraction patterns were collected and analyzed with the Rietveld method. The analysis showed that the Li substitutes onto the La site in the rhombohedral perovskite lattice. Resistivities were measured between 4.2 K and room temperature in the magnetic fields of 0, 1, 2, 4, 8, and 13 T. A wide semiconductor-metal transition at temperatures between 160 and 210 K or between 200–230 K were observed for both samples with x=0.2 and 0.3, respectively. Large magnetoresistances above 20%–80% were achieved at fields from null to 13 T over a wide temperature range from the ferromagnetic transitions down to 4.2 K. However, the x=0 and 0.1 samples show a semiconducting behavior in resistivity measured between 77 and 300 K.