Griffiths-Like Phase in Nanocrystalline Manganite $La_{0.85}Ca_{0.15}MnO_3$

The ferromagnetic Curie temperatures $T_{C}$ derived from a temperature derivative of AC susceptibility are equal to 106 K and 161 K for the nanocrystalline and polycrystalline manganites, respectively. The magnetic susceptibility and electron spin resonance confirm that the Griffiths-like phase exists above the Curie temperature in paramagnetic matrix of the nanocrystalline manganite. An analysis of electron spin resonance spectra allows to detect the upper temperature limit for an existence of Griffiths-like phase at temperature $T_{GI}=290 K$, which is somewhat higher than the $T_{G}$ of the magnetic susceptibility.