Co-existence of Griffiths phase and ferromagnetic insulating state in electron doped nanomanganite

Detailed temperature dependent magnetic and transport properties of electron doped Sm0.09Ca0.91MnO3 nanomanganite exhibiting Griffiths phase (GP) have been investigated. A GP-like behavior having ferromagnetic spin correlation above ferromagnetic transition temperature (TC) without any spontaneous magnetization has been observed in this nanomanganite. Moreover, in this electron doped nanomanganite, the experimental large effective magnetic moment and deviation of the inverse susceptibility from Curie-Weiss law clearly indicate the possible existence of GP. The complex non-linear ac susceptibilities (2nd and 3rd harmonics) have also been studied to explore the role of nature of disorder in the GP phenomenon. The transport measurements yield a ferromagnetic insulating ground state exhibiting colossal magneto resistance (CMR) near the ferromagnetic transition temperature. It has also been reported that the temperature dependent average spin moment at the hopping site and the ferromagnetic phase fraction bear the signature of the onset of GP.