Phase Transition and Anomalous Low Temperature Ferromagnetic Phase in Pr0.6Sr0.4MnO3 Single Crystals

We report on the magnetic and electrical properties of Pr0.6Sr0.4MnO3 single crystals. This compound undergoes a continuous paramagnetic-ferromagnetic transition with a Curie temperature T C∼301 K and a first-order structural transition at T S∼64 K. At T S, the magnetic susceptibility exhibits an abrupt jump, and a corresponding small hump is seen in the resistivity. The critical behavior of the static magnetization and the temperature dependence of the resistivity are consistent with the behavior expected for a nearly isotropic ferromagnet with short-range exchange belonging to the Heisenberg universality class. The magnetization (M–H) curves below T S are anomalous in that the virgin curve lies outside the subsequent M–H loops. The hysteretic structural transition at T S as well as the irreversible magnetization processes below T S can be explained by phase separation between a high-temperature orthorhombic and a low-temperature monoclinic ferromagnetic phase.