The dynamics of magnetization in phase separated manganite around half doping: A case study for Pr0.5Sr0.5Mn0.925Ga0.075O3

We investigate the magnetization dynamics in a phase separated half-doped manganite after introducing nonmagnetic quenched disorder Ga at Mn-site. The compound, Pr0.5Sr0.5Mn0.925Ga0.075O3, exhibits a new magnetic anomaly at low temperature. Our detailed study shows this phase arises due to thermal blocking of embedded nanometer size ferromagnetic clusters, demonstrating superparamagnetic behavior. The system, however, exhibits slow magnetic relaxation, aging and memory effect which are believed due to collective behavior induced by the intercluster interactions. Our results imply that the dynamics can be explained by the hierarchical model rather than droplet model which are commonly used for spin glass dynamics. -- Highlights: ► Magnetization dynamics are studied in phase separated Pr0.5Sr0.5Mn0.925Ga0.075O3. ► At low temperature, a new magnetic phase is developed. ► This is due to thermal blocking of nanometer size embedded ferromagnetic clusters. ► There are intercluster interactions which render correlated dynamics. ► The dynamics can be explained by Hierarchical model, commonly used for spin glass.