Oxygen Isotope Effect in Ordered PrBaMn_2O_6

摘要

The oxygen isotope effect in ordered half-doped manganite PrBaMn_2~(16-18)O_6 has been investigated. Real and imaginary parts of ac magnetic susceptibility, dc magnetization and magnetoresistance were measured at temperatures from 4.2 to 320 K in applied magnetic field up to 35 kOe. Substantial increase of charge ordering (CO) transition temperature TCO under oxygen isotope substitution ~(16)O→~(18)O and small decrease of ferromagnetic (FM) transition temperature T_(FM) were found. Small systematic shift of ferromagnetic transition temperature in oxygen reduced manganite PrBaMn_2~(16-18)O_5 is also considered. The obtained results are compared with those observed in other manganites demonstrating the large isotope effect.