Abstract

[ R_1/3Sr_2/3FeO_3 ](R=Pr, Nd, and Sm) was synthesized and their magnetic properties and charge ordering(CO) transition related with lattice dynamics and oxygen vacancy were systematically investigated. The charge disproportion ation(CD) in R_1/3Sr_2/3FeO_3(R=Pr,Nd) was in which two kins of iron with valence state Fe3+ and Fe5+ were found with ratio of 2:1. In this charge ordering state a sequence of Fe3+Fe3+Fe5+Fe3+Fe3+Fe5+ exists aligned along the [111] direction of the pseudocubic perovskite structure. The charge ordering exist in distorted structure involving t_pd hybridization. The disordering phases coexist in distorted structure as temprature in creases that is controlled amount of oxygen vacancy. The magnetic hyperfine fields indicate charge tranfering temperature as it dissapeared drastically.

• Keywords: Charge ordering;Single crystal;Perovskite;