Evolution of the magnetic phase diagram of CMR manganites after oxygen isotope substitution

Oxygen isotope effect in magnetic properties of CMR manganites of the (La1- yPry)(0.7)Ca0.3MnO3 system was systematically studied. Substitution of O-16 by O-18 was found to stabilize insulating state and suppress ferromagnetic (FM)component. The AC susceptibility data revealed a pronounced temperatur e hysteresis. The hysterisis became more pronounced with increase of y up t o 0.75, The width of the hysteretic loops was strongly affected by the O-16 --> O-18 substitution. The T-y phase diagram and its evolution due to oxyg en isotope substitution are analyzed. (C) 2000 Elsevier Science B.V. All ri ghts reserved.