Asymmetric phase diagram and phase separation in Pr_0.5-δCa_0.2+δSr_0.3MnO₃ (-0.04≤δ≤0.04)

We present electric and magnetic properties of polycrystalline Pr_0.5-δCa_0.2+δSr_0.3MnO₃, for δ between -0.04 and 0.04, where the hole concentration is n=0.5+δ. In this series, we study the effects of moving n away from 0.5 on both, the phase diagram and phase separated state. We found that the low temperature ferromagnetic fraction X_FM continuously decreases when n increases. As a result, the samples with n<0.5 (large X_FM) exhibit metallic resistivity at low T while for n>0.5 the insulating state predominates. We construct a detailed T-n phase diagram showing the asymmetries around half-doping.