【摘要】 Mn位掺杂是调整稀土锰氧化物中Mn3+-O2--Mn4+网络的一种十分有效的方法,对理解稀土锰氧化物材料的物理机制和微观机理具有重要作用。在Ln1-xAxMnO3体系中,当x=0.3左右时,Mn位微量掺杂即可破坏原有的长程铁磁有序与金属性共存,而产生团簇玻璃型(短程)铁磁有序行为;多数情况下,TP降低,对应的峰值电阻率ρp急剧升高,居里温度TC降低,CMR效应增强。当x=0.5时,通过在Mn位掺杂可以使反铁磁绝缘母体产生铁磁金属性行为;电阻率急剧降低,出现CMR效应。更多还原

【Abstract】 An interesting way to modify the crucial Mn³⁺-O^2--Mn⁴⁺ network is to dope at the Mn site.For Ln_1-xA_xMnO₃（x～0.3）,the doping of even a small amount of transition metal ions at Mn site tends to destroy the long-range FM order and leads to the cluster-glass type.It was found that all these doping reduce the ferromagnetic（FM） transition temperature T_C and the metal-insulator transition temperature T_P.The resistivity of the peak temperature Tp and the CMR effect increase.For x=0.5,the doping at the Mn-site leads to the FM metallic state at the expense of the AFM insulated state.The resistivity decreases rapidly and the CMR effect was induced.更多还原