Nanoscale observation of room-temperature ferromagnetism on ultrathin (La,Ba)MnO3 films

We have fabricated La0.8Ba0.2MnO3 ultrathin films with an atomically flat surface and have systematically investigated the magnetism for film thickness dependence. The 20-nm-thick film showed a maximum peak of T-C (310 K). It was found that even the 5-nm-thick film showed a T-C of 290 K near room temperature, which opens up the possibility of spin devices working at room temperature. Furthermore, we have adopted noncontact magnetic force microscopy to evaluate local magnetization in ultrathin (La,Ba)MnO3 films, and confirmed that several tens of nanocale ferromagnetic domains appear at room temperature. (C) 2003 American Institute of Physics.