Evidence of electronic phase separation in Er3+-doped La0.8Sr0.2MnO3

Er3+ doping at the La site in La0.8Sr0.2MnO3 showed an unusual increase in Curie/peak resistivity temperature (TC/TP) above a certain nominal dopant concentration (x⩾0.086). This increase is attributed to the presence of a cation-deficient ErMnO3 phase. Further, with increase in TP the overall resistivity of these compounds also decreases. We explain these results assuming the presence of a nanoscale mixture of charge-ordered antiferromagnetic insulating (CO-AFMI) phase in a ferromagnetic metallic matrix, wherein the increase in TC/TP with increase in Er3+ content is due to the local destruction of the CO-AFMI phase by the presence of the cation-deficient ErMnO3 phase. We thus provide an indirect evidence of electronic phase separation in these compounds.