Suppression of a glassy magnetic state and emergence of a Griffiths-like phase on size reduction in Nd0.8Sr0.2MnO3

摘要

A detailed study of the effect of grain size reduction on the spin glass like phase in Nd0.8Sr0.2MnO3 has been carried out. A rigorous measurement of linear and non-linear ac magnetic susceptibility in the bulk-like Nd0.8Sr0.2MnO3 confirms the existence of a glassy phase in the low temperature regime. The effect of size reduction on this glassy state is addressed here. This glassy phase is found to strongly destabilize on reduction of grain size down to a value of 42 nm. Based on our experimental results, the glassy phase has been attributed to the phase separation effect and interaction between the ferromagnetic clusters. The destabilization of this glassy phase has been argued to be due to the modification of the phase separated state on size reduction. Furthermore, the lowest grain size sample displays a Griffiths-like phase. The evidence of the emergence of this phase has been obtained from detailed dc and ac magnetization studies. We have explained our results through a phenomenological model.