Critical analysis of the paramagnetic to ferromagnetic phase transition in Pr0.55K0.05Sr0.4MnO3

The critical properties of monovalent doped manganite Pr0.55K0.05Sr0.4MnO3 around the
paramagnetic to ferromagnetic phase transition were investigated through various methods: the
modified Arrott plots (MAP), the Kouvel-Fisher method and the critical isotherm analysis. Data
obtained near Tc were examined in the framework of the mean field theory, the 3D–Heisenberg
model, the 3D–Ising model, and tricritical mean field. The deduced critical exponents values
obtained using MAP method were found to be β = 0.44(4) with TC ~ 303 K and γ = 1.04(1)
with TC ~ 302 K. Kouvel-Fisher method supplies the critical values to be β = 0.41(2) with TC ~
302 K and γ = 1.09(1) with TC ~ 302 K. The obtained critical parameters show a tendency
towards the mean-field behavior, suggesting the existence of long-range ferromagnetic order in
the compound studied. The exponent δ deduced separately from isotherm analysis at T= 303 K
was found to obey to the Widom scaling relation δ = 1+ γ/ β. The reliability of obtained
exponents was confirmed by using the universal scaling hypothesis. The itinerant character of
ferromagnetism in the present system was also tested by using Rhodes-Wohlfarth’s criterion.