Modification of the ground state in Sm-Sr manganites by oxygen isotope substitution

The effect of O-16-->O-18 isotope substitution on electrical resistivity and magnetic susceptibility of Sm1-xSrxMnO3 manganites is analyzed. It is shown that the oxygen isotope substitution drastically affects the phase diagram at the crossover region between the ferromagnetic metal state and that of antiferromagnetic insulator (0.4