掺杂TiO_2的La_(2/3)Ba_(1/3)MnO_3电输运与磁电阻特性

Transport and Magnetoresistance Properties in TiO_2-Doped La_(2/3)Ba_(1/3)MnO_3

通过固相反应法制备了(1-x)La2/3Ba1/3MnO3+xTiO2(x=0%～5%)多晶陶瓷样品.实验发现,随着TiO2掺杂量的增加,电阻率明显增大,金属-绝缘相转变温度Tp值下降.通过室温(300K)和低温(78 K)下不同磁场的磁电阻计算表明,适量的TiO2掺杂会明显提高材料的磁电阻性能;在1T磁场下,TiO2掺杂量为1%的样品室温磁电阻达到12%,这是未掺杂La2/3Ba1/3MnO3相同条件下的3倍,为磁电阻传感器研究提供了实验依据.

(1-x)La_(2/3)Ba_(1/3)MnO_3+xTiO_2(x=0%-5%) polycrystalline ceramic samples were prepared by solid-state-reaction method. It is found that with increasing TiO_2 doping level, the resistivity increases obviously, and the metal-insulator transition temperature T_p decreases. The magnetoresistances measured in different magnetic fields at room temperature(300 K) and low temperature (78 K) show that moderate TiO_2 dopant can enhance the magnetoresistance obviously. The magnetoresistance for the sample with 1% TiO_2 dopant in 1T magnetic field reaches 12% at room temperature, which is 3 times larger than undoped La_(2/3)Ba_(1/3)MnO_(3) under the same condition,which provides the experimental proof for the magnetoresistance sensor research.