Effect of particle size on the structural and magnetic properties of La0.8Sr0.2MnO3

In this study, we have investigated the effects of grain size on the structural and magnetic properties of La0.8Sr0.2MnO3 powder samples. The Williamson-Hall method was employed on the x-ray peak profile of these powder samples to determine the lattice microstrain. It was found that the microstrain increases by decreasing grain size. The magnetization decreases by decreasing grain size. A decrease in magnetization by decreasing grain size indicates formation of magnetically dead layer at the surface of grains. The thickness of such a magnetically dead layer increases by decreasing particle size. It seems that one of the sources for the formation of this magnetically dead surface layer is the microstrain. By subsequently annealing at a temperature of 800 degrees C, the microstrain was released partially and magnetic properties were improved. (c) 2006 American Institute of Physics.