Critical Behavior in La0.75Ca0.2Ag0.05MnO3 Exhibiting the Griffiths Phase

In this paper, we have investigated the critical properties in the vicinity of the ferromagnetic (FM)-paramagnetic (PM) phase transition in a polycrystalline sample of La
_0.75
Ca
_0.2
Ag
_0.05
MnO
₃
, which was prepared by a solid-state reaction method. Temperature dependence of the inverse of the susceptibility χ
^-1
(T) proves an existence of the Griffiths phase well above Curie temperature (TC = 230 K). Detailed analyses of the isothermal magnetization M(H, T) data reveal the sample exhibiting a second-order magnetic phase transition, and its temperature dependences of the saturation magnetization and the initial susceptibility obey the asymptotic relations. Using the modified Arrott plots method, the Kouvel-Fisher method, and the critical isotherm analysis, the critical parameters (β, γ, δ, and TC) of La
_0.75
Ca
_0.2
Ag
_0.05
MnO
₃
compound have been estimated. Using these critical exponent values, almost M(H, T) data measured at different temperatures around FM-PM phase transition are collapsed onto two universal curves of M/|ε|
^β
versus H/|ε|
^β+γ
corresponding to the regular functions for T > T
_C
and T <; T
_C
, respectively.