研究了La位Gd掺杂对La_(0.7-x)Gd_xSr_(0.3)MnO_3(x=0.00,0.10,0.15,0.20,0.30,0.40,0.50,0.60,0.70)体系的电输运性质和磁阻效应的影响。实验结果表明:高掺杂时的输运性质发生异常,在x=0.50时,发现了在ABO_3结构中很少出现过的在T_c附近发生绝缘-金属相变之后又发生从金属到绝缘相变的现象;对x=0.60,0.70体系在远离T_c的温区就表现为绝缘体。这些反常行为归因于不同的磁背景,即体系由长程铁磁有序向自旋团簇玻璃态、反铁磁状态转变。 The electrical transport properties and magnetoresistance effects of La-Gd doping on La 0.7-x Gd x Sr 0.3 MnO 3 (x = 0.00,0.10,0.15,0.20,0.30,0.40,0.50,0.60,0.70) Impact. The experimental results show that the transport properties at high doping are anomalous. At x = 0.50, it is found that the phase transition from metal to insulator occurs in the vicinity of T_c, which is rare in ABO_3 structure. Of the phenomenon; for x = 0.60,0.70 system in the temperature away from T_c on the performance of the insulator. These anomalous behaviors are attributed to different magnetic backgrounds, ie the transition from long-range ferromagnetic order to spin-cluster glassy and anti-ferromagnetic states.