Reentrant Spin Glass Behaviour and CE-Type Antiferromagnetic Phase in Half Doping （La,Pr）1／2Ca1／2 MnO3 Manganites

The reentrant spin glass behaviour was observed in half doping (La,Pr)1/2Ca1/2MnO3 manganites with a CEtype antiferromagnetic structure. It shows sequential multiple magnetic transitions from the paramagnetic to the ferromagnetic, antiferromagnetic, spin glass (SG) transitions, which reflects the complex magnetic interaction in the ground state of manganites. This can be explained by the competition interaction between the ferromagnetic and the CE-type antiferromagnetic matrix, and the disorder due to the tolerance factor t and A-cation size variance σ^2. The results reveals the coexistence of ferromagnetic clusters and SG clusters in the background of the antiferromagnetic matrix in the ground state of half doping (Pr,La)1/2Ca1/2MnO3 systems.