1000% colossal magnetoresistance at room temperature in the A-site ordered perovskite manganites, Sm_(1-x)La_(x+y)Ba_(1-y)Mn_2O_6

摘要

We report colossal magnetoresistance at room temperature by introducing disorder to the A-site ordered manganites, SmBaMn_2O_6. SmBaMn_2O_6 shows the metal to CE-type charge/orbital ordered insulator transition at 375 K above room temperature. We have achieved a magnetoresistance effect of 340% at room temperature and 300%-600% around room temperature under 9 T in a sintered sample of Sm_(0.90)La_(0.24)Ba_(0.86)Mn_2O_6. By using a single crystal the magnetoresistance (%) was elevated to 1000% at 9 T, a high value for bulk transition-metal oxides.