Critical Behavior in La 0.75 Ca 0.2 Ag 0.05 MnO 3 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 $\chi ^{-1}$ ( $T$ ) proves an existence of the Griffiths phase well above Curie temperature ( $T_{C} = 230$ 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 ( $\beta$ , $\gamma$ , $\delta$ , and $T_{C}$ ) 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 $M/\vert \varepsilon \vert ^{\boldsymbol {\beta }}$ versus $H/\vert \varepsilon \vert ^{\boldsymbol {\beta }+\boldsymbol {\gamma }}$ corresponding to the regular functions for $T > T_{C}$ and $T , respectively.