采用固相法制备了Pr0．45（Ca1-xSrx）0．55MnO3（x=0．0，0．2，0．4，0．6，0．8，1．0）多晶样品．通过测量样品的X射线衍射（XRD）谱、磁化强度-温度（M～T）曲线、电阻率-温度（ρ～T）曲线，研究了Sr^2＋替代Ca^2＋对Pr0．45Ca0．55MnO3体系磁性和电性的影响．实验发现：随带宽增大，磁性增强，电荷有序相逐渐减弱并最终融化；与磁测量相对应，电荷有序融化后，电阻率突降了几个数量级；电荷有序态体系导电机制是可变程跃迁，电荷有序破坏后转为小极化子绝热跃迁．体系在极低温41K附近发生自旋玻璃转变．
The polycrystalline samples of Pr0.45（Ca1-xSrx）0.55MnO3 （x=0. 0, 0. 2, 0. 4, 0. 6, 0. 8, 1.0） are prepared by solid-state reaction. Influence of Sr^2＋ substitution for Ca^2＋ at A site on transport properties and magnetic properties is studied through the measurements of X-ray diffraction （XRD） spectrum, the magnetization -temperature （M-T） curves and the resistivity-temperature （ρ-T） curves. The results show that the magnetism strength- ens, and charge ordering becomes weaker and it is melted completely at last with the increasing of bandwidth. The resistivity decreases by, several orders of magnitude suddenly after the melting of charge-ordering （CO） phase, which is corresponding to magnetism. The conductive mechanism of charge-ordering （CO） phase system is the variablerange hopping of charge carriers, and it becomes the small polaron adiabatic transport behavior after the melting of charge-ordering （CO） phase. The spin-glass behavior appears at about 41K.
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