Cr-doping effect on the perovskite (Nd, Sr) MnO3 single crystals

The effect of Cr-doping on the Mn site in Nd1-ySryMnO3 (y = 0.5 and 0.55) single crystals grown by the floating zone method has been studied. The y = 0.5 mother material exhibits a transition at T-C = 260 K to be a ferromagnetic metal (FMM) and at T-N = 160 K to be an antiferromagnetic insulator (AFMI). The doping of 5 at% Cr3+ ions lowers T-C to be 250 K and completely suppresses the AFMI. The v = 0.55 mother material exhibits a transition at T-N = 230 K to be an antiferromagnetic metal. The doping of 5 at% Cr3+ ions changes the state to be similar to y = 0.5 mother material having the FMM and AFMI. The doping of 10 at% Cr3+ ions completely suppresses the AFMI and keeps the FMM. In both cases, small amount of Cr-doping stabilizes the FMM, which is probably caused by provoking the double exchange interaction between Mn3+/Mn4+ pairs. (C) 2002 Elsevier Science B.V. All rights reserved.