Phase separation induced by oxygen isotope substitution in manganites of the Sm1−xSrxMnO3 system

Abstract

The effect of 16 O → 18 O isotope substitution on the electrical and magnetic properties of the manganite system Sm 1− x Sr x MnO 3 has been studied. It is shown that oxygen isotope substitution brings about a substantial change in the phase diagram in the intermediate region 0.4< x <0.6 between the ferromagnetic metal and antiferromagnetic insulator regions and induces phase separation and transformation of the ground metallic into insulating state for x =0.475 and 0.5. The specific features of the metal-insulator transitions in the Sm-Sr system and the nature of the low-temperature phase are discussed.