Jing Chao

Ferromagnetic resonance in Co/Pt multilayers

Out-of-plane angular dependence of ferromagnetic resonance spectra was measured in sputtered Co/Pt multilayers and analyzed with the Landau-Lifshitz-Gilbert equation. The effective demagnetizing field 4πMeff is found to increase with decreasing tPt and decreasing 1/tCo, which can be considered as a result of interplay between the interlayer coupling and a low-dimensional effect. The g factor increases with increasing tPt and decreasing tCo, indicating contribution of spin-polarization of Pt atoms and additional contribution of orbital moment of Co atoms. The in-plane resonance line-width increases with decreasing tCo and increases with increasing tPt.

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 CE-type 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 ?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.