Critical end point of the first-order ferromagnetic transition in a Sm0.55(Sr0.5Ca0.5)0.45MnO3 single crystal

• System shows a strong first-order ferromagnetic to paramagnetic phase transition.
• Extremely sharp metal–insulator transition at around 82 K.
• The value of critical magnetic field at which first-order transition becomes a crossover is highest among manganites.
• The nature of transition is sensitive to external perturbations such as magnetic field and pressure.

We report on the magnetic field (H) and hydrostatic pressure (P) dependence of the order of the ferromagnetic (FM) to paramagnetic phase transition in a Sm0.55(Sr0.5Ca0.5)0.45MnO3 single crystal. At ambient condition, the system exhibits a first-order FM transition at TC≈82K (in heating cycle) with strong thermal hysteresis (~13 K). The application of external H and P increases TC, suppresses the hysteresis width, and thus weakens the first-order nature of the transition. Our analysis reveals that the hysteresis vanishes and the first-order FM transition becomes a crossover above a critical magnetic field Hcr≈11.5T. The value of Hcr is highest among the manganite family, although the first-order nature of the FM transition is believed to be strongest in Eu1−xSrxMnO3(x≈0.45).