Ferromagnetic transition and specific heat of Pr0.6Sr0.4MnO3

The critical properties of orthorhombic Pr${}_{0.6}$Sr${}_{0.4}$MnO${}_{3}$ single crystals were investigated by a series of static magnetization measurements along the three different crystallographic axes as well as by specific heat measurements. A careful range-of-fitting-analysis of the magnetization and susceptibility data obtained from the modified Arrott plots shows that Pr${}_{0.6}$Sr${}_{0.4}$MnO${}_{3}$ has a very narrow critical regime. Nevertheless, the system belongs to the three-dimensional (3D) Heisenberg universality class with short-range exchange. The critical exponents obey Widom scaling and are in excellent agreement with the single scaling equation of state $M(H,\ensuremath{\epsilon})={|\ensuremath{\epsilon}|}^{\ensuremath{\beta}}{f}_{\ifmmode\pm\else\textpm\fi{}}{(H/|\ensuremath{\epsilon}|}^{(\ensuremath{\beta}+\ensuremath{\gamma})}$; with ${f}_{+}$ for $Tg{T}_{c}$ and ${f}_{\ensuremath{-}}$ for $Tl{T}_{c}$. A detailed analysis of the specific heat that account for all relevant contributions allows us to extract and analyze the contribution related to the magnetic phase transition. The specific heat indicates the presence of a linear electronic term at low temperatures and a prominent contribution from crystal field excitations of Pr. A comparison with data from literature for PrMnO${}_{3}$ shows that a Pr-Mn magnetic exchange is responsible for a sizable shift in the lowest lying excitation.