Improvement on Electrical Properties and Magnetoresistance Induced by Pd or Ag Addition in Lao.67（Ca0.65Ba0.35）0.33MnO3 Manganites  

Pd／Ag掺杂的LaoBT（Ca0.65Ba0.35）0．33MNO3体系电特性和磁电阻增强效应

作　　者：原晓波[1] 任俊峰[1] 

机构地区：[1]山东师范大学物理与电子科学学院,济南250014

出　　处：《Chinese Journal of Chemical Physics》2013年第4期431-438,J0002,共9页化学物理学报（英文）

摘　　要：Electrical properties and magnetoresistance have been studied in two series of xAg-La0.67（Ca0.65Ba0.35）0.33MnO3 and xPd-La0.67（Ca0.65Ba0.35）0.33MnO3 （abbreviated by xAg-LCBMO and xPd-LCBMO） composites. Both Pd and Ag addition induce a decrease in resistivity and an increase in temperature at which the resistivity reaches its maximum. This is mainly due to the improvement of grain boundaries caused by the segregation of good conductive metal grains on the grain boundaries/surfaces. In addition, both Pd and Ag addition induce a large enhancement of room temperature magnetoresistance （RTMR）. Note that 27% molar ratio of Ag addition induces a large RTMR of about 70%, about ten times larger than pure LCBMO, whereas 27% molar ratio Pd addition brings a much larger RTMR of about 170%. The large enhancements of MR can be attributed to the decrease in resistivity of the samples caused by the good conductive metal. On the other hand, the polarization of Pd atoms near the Mn ions on the grain surfaces/boundaries plays a very im-portant role in the increase in MR, which induces a large number of spin clusters in Pd-added samples.

关 键 词：Colossal magnetoresistance Ag-added manganite Pd-added manganite Roomtemperature magnetoresistance Spin cluster Polarization of Pd atom 

分 类 号：O[理学]