Magnetic and electric properties of the colossal magnetoresistance manganite SM1.4Sr1.2Ca0.4Mn2O7

摘要

Polycrystalline Sm1.4Sr1.2Ca0.4Mn2O7 has been successfully synthesized and investigated with respect to its magnetic and electrical properties. It is found that the sample shows a metal insulator (M-I) transition at 88 K. The maxima of the magnetoresistance (MR) ratio are 95.38% and 98.55% under applied fields of 2 T and 5 T, respectively. At 10 K, the MR attains similar to 75% at 5 T. The large MR at low temperature can be attributed to the effects of nearly fully spin-polarized carriers tunneling through the insulating (Sm, Sr, Ca)(2)O-2 layers between the adjacent MnO2 bi-layers. The magnetization data indicates the existence of ferromagnetic clusters. (C) 2006 Elsevier Ltd. All rights reserved.