La2/3Ca1/3MnO3:Agx多晶靶材的制备及其电输运性质

摘要

Ag-doped polycrystalline La2/3Ca1/3MnO3(LCMO) : Agx (x = 0. 00, 0.01, 0. 05, 0. 10, 0. 20, 0.30, 0.40) targets have been prepared by solid-phase sintering method. X-ray diffraction (XRD) patterns show that the samples have a pseudo-cubic perovskite structure. With the addition of Ag, there is a little change in a-axis and b-axis from x=0. 00 to x= 0. 40. In addition, R-T curves demonstrate that the metalinsulation transition temperatures (Tp) increases sharply for x＜0.05, and then increases slowly for x=0.05-0.40. The maximum Tp is 192 K, which is 80 K lower than that made by chemical coprecipitation method. This may be explained by the influence of powder grain size on Tp.%采用固相反应法制备了不同Ag掺杂量的La2/3Ca1/3MnO3(LCMO)∶Agx(x为摩尔百分比,x=0.00、0.01、0.05、0.10、0.20、0.30、0.40)多晶靶材,XRD图谱显示所制备样品均为纯相的赝立方钙钛矿结构,并且随着Ag掺杂量的增加,a轴和b轴在0≤x≤0.40范围内有微小的涨落;另外RT曲线显示,0≤x≤0.05时,金属-绝缘转变温度(Tp)开始升高很快,0.05＜x≤0.40时逐渐变缓,最大值为192K,这比化学共沉淀法制备的多晶靶材(273K)低约80K,分析其原因可能是粉体粒度的不同所致.