Effects of oxygen distributions to magnetic properties of nanoparticle La2CuO4

The long-range magnetic transition temperature of La2CuO4 (LCO) was found to be strongly suppressed by reducing the particle size down to the nanometer scale. We also revealed from our previous muSR study that a clear phase separation into long-range and short-range ordered states appeared in nanoparticle LCO. We suggest that reason of the phase separation was due to the existence of oxygen distributions between the two phases. On the other hand, magnetic properties measured by SQUID on nanoparticle LCO's which were annealed in different atmosphere gas conditions did not show large differences. We are guessing that this unchanged magnetic property is a new possible character of the nano-size effect on LCO. Accordingly, we propose to measure changes in TN of systematically annealed nanoparticle LCO to investigate effects of oxygen distribution to magnetic properties of nanoparticle LCO.