Ag掺杂对La_(2/3)A_(1/3)MnO_3(A=Ca、Sr、Ba)材料电学性能的影响

Effects of Ag Doping on the Electrical Properties of La_(2/3)A(1/3)MnO_3(A=Ca, Sr, Ba) Composites Materials

采用化学共沉淀法制备了La2/3A1/3MnO3:Agx(A=Ca、Sr、Ba,LAMO:Agx,x=0、0.1、0.2、0.3、0.4 mol%)多晶复合材料。XRD结果表明实验制备了纯相LAMO:Agx样品,Ag+离子A位替代致使LCaMO:Agx和LSrMO:Agx晶格常数和晶胞体积发生微小膨胀,LBaMO:Agx晶格常数和晶胞体积发生微小收缩;R-T测试结果表明LCaMO:Agx的电阻温度系数(Temperature Coefficient of Resistance,TCR)数值在x=0.4、Tk=271.3 K(Tk为TCR位于最大值时对应的温度数值)时具有最大值为28%/K。SEM分析结果表明,随着Ag掺杂量增加,LCaMO晶粒尺寸增大,晶粒均匀性和规则性得以改善,晶化质量得到提高。通过Ag微观掺杂机制对LAMO复合材料的TCR数值增强进行了分析讨论。

La2/3A1/3MnO3：Agx（A=Ca, Sr, Ba, LAMO：Agx, x=0, 0.1, 0.2, 0.3, 0.4, mol%） composites materials were prepared successfully by co-precipitation route. XRD results showed that the pure phase LAMO：Ag~ samples were obtained. By substitution of A site with Ag ion, the crystal lattice and cell volume were expanded slightly for LCaMO： Agx and LSrMO：Agx, but shrinked slightly for LBaMO：Ag~ R-T measurement results showed that the maximum tem- perature coefficient of resistance （TCR） of LCaMO：Agx composites reached 28%/K as x=0.4, Tk=271.3 K （Tk： tem- perature at the maximum TCR value）. SEM images showed that for LCaMO composites, the particle size were enlarged. The uniform, homogeneity and crystal quality were improved with increase of Ag doping. The TCR en- hancement of LAMO：Agx composites are discussed by the microscopic mechanism with Ag doping.