Stabilization of antiferromagnetic phases by magnetic field annealing in phase separated manganites Pr1−xCaxMnO3

We report a detailed study on the effects of magnetic field annealing on the magnetic and transport properties of single crystals of Pr1−xCaxMnO3 with x = 0.2 – 0.4 . Below the Néel temperature, the samples with 0.3 ≤ x ≤ 0.35 undergo a typical metamagnetic transition from antiferromagnetic (AFM) to ferromagnetic (FM) upon applying a field of about 3 T. After the first metamagnetic transition, remarkably, the critical field of the second metamagnetic transition is increased by about 1 T, suggesting that the AFM phase is stabilized by the magnetic field-annealing. This field-stabilized AFM phase might be attributed to the coexistence of inhomogeneous FM and AFM phases near the phase boundary that are strongly dependent upon a magnetic field. A general phase diagram of Pr1−xCaxMnO3 is thus modified on the basis of irreversible magnetic transitions.