中文摘要：

采用传统固相反应法制备了La0．67Ba0．33Mn1-xZnxO3（O≤z≤0．2）多晶样品，系统研究了Zn掺杂对于多晶样品的结构，磁性和电输运性质的影响．XRD衍射表明样品均具有单一的立方钙钛矿结构．在外加磁场（H-10000e）环境中测得的磁化强度温度（M-T）曲线表明，在5-350K的温区内所有样品均发生了顺磁相（PM）到铁磁相（FM）的转变．样品的居里温度（Tc）和磁化强度随着Zn的掺杂量的增加呈现下降的趋势，当X=0．1时，样品的R和磁化强度与未掺杂的样品相比下降的幅度不大．但是当X=0．2时，样品的Tc和磁化强度都发生明显的下降．从零场（H-0T）和外加磁场（H=2T）下测得的电阻温度曲线可见，样品在测量的温区范围内均发生绝缘相到金属相的转变．随着掺杂量的增加绝缘-金属相转变温度（TIM）向低温区移动，但是样品的电阻逐渐增大．所有样品在TM附近呈现均出现磁电阻（^很）峰，随着Zn的掺杂量的增加MR值由X=0时的-22％（T=314．5K）增加到X=O．2时的-73％（T=80K），且样品的磁电阻温区被明显拓宽．

英文摘要：

The Zn-doping La0.67Ba0.33Mn1-xZnxO3 （0≤x≤0. 2）samples have been prepared by conventional solid- state reaction method. We have systematacially investigated the influence of Zn-doping on the structure, transport properties and magnetoresistance. The X-ray diffraction results revealed that all the samples exhibits simple cubic perovskite structure at room temperature. The M~ T curves for zero filed-cooled（ZFC）condition in a magnetic filed of 1000Oe suggests that with the increase of the temperature all the samples exhibit a ferromagnetic to paramagnetic phase transition. The Curie temperature and the intensity of magnetization are found to decrease upon Zn doping. Compared with un-doping samples, when x = 0. 1 the Curie temperature and intensity of magnetization of all the sam- pies have no obvious change but when x= 0. 2 the Curie temperature and intensity of magnetization experience a re- markable decrease. The temperature dependence of resistance curves are measured under H=OT and H=2T, which reveals a metal-insulator transition, with the substitution of Zn the Tc move to low temperature zone, but the re-sistance of all the samples increase gradually. All samples around Tc appear a peak of MR, the value of MR increa- ses from - 22 %（x= 0. 0） to - 73 % （x= 0. 2）. With the increasing of doping amounts, the temperature zone of MR has been widened.