6587
博碩士論文
field-cooling , zero-field-cooling , long range spin ordering , short range spin ordering , resistivity , ferromagnetic transition temperature , antiferromagnetic , spi nordering , ferromagnetic , superexchange interaction , magnetoresistance ratio , saturation magnetization , perovskite , rhombohedral , orthorhombic , colossal magnetoresistance , double-exchange interaction
The hole-doped perovskite manganese oxide such as Ln1-xAxMnO3 (Ln = La, Nd, Pr, and A = Ca, Sr, Ba, Pb) is one of the most studied topics in the recent years due to the observation of colossal magnetoresistance (CMR). Basically, LaMnO3 has an almost insulating behavior and on antiferromagnetic arrangement. By substituting a divalent cation (A2+) in place of La3+, LaMnO3 can be driven into metallic and ferromagnetic state. Mixed valence of Mn 3+ / Mn4+ is needed for both metallicbehavior and ferr...