Substantial Ca doping site effect on structure of La0.5Ca0.5MnO3 at low temperature

Six possible structures of La_0.5Ca_0.5MnO₃ corresponding to different Ca doping sites are studied at low temperature using atomistic simulation techniques. It is found that Ca doping site has substantial effect on structure of La_0.5Ca_0.5MnO₃ and this effect may explain the existence of four similar phases with slightly different lattice parameters in La_0.5Ca_0.5MnO₃ at low temperature. Structures I and II are found to be favorable La_0.5Ca_0.5MnO₃ structures. They have an ordering arrangement of La³⁺ and Ca²⁺ ions and different arrangements of Mn³⁺ and Mn⁴⁺ ions, which may affect the charge, orbital and magnetic ordering in La_0.5Ca_0.5MnO₃ at low temperature.