Electronic Structure and Magnetic Properties of Molecular Magnets and Metal-Oxide Nano-Particles

Jaejun Yu

School of Physics, Seoul National University

We report our first principles calculation studies of the electronic structure and magnetic properties of single-molecular magnets as well as metal-oxide nano-particles. Often nano-sized particles exhibit qualitatively different behavior from their bulk state due to the different contributions from surfaces as well as local environments. For examples, the magnetic properties of magnetic molecules are affected by the presence of ligand molecules, and the MnO nano-particles show ferromagnetic behavior while the bulk MnO being antiferromagnetic. For the calculations, we used the localized pseudo-atomic orbital method based on the density functional theory within local density approximation. We calculated the electronic structures of Mn_n clusters to investigate the role of ligand in single-molecular magnets. The detailed analysis reveals an important contribution of the bridging carbon atoms, connecting the Mn-O core and the outer ligand complex, to the magnetic ground states of the magnetic molecules. Also we present our first-principles calculation results of the several types of MnO nano-clusters and suggest a possible origin of ferromagnetic components observed in MnO nano-particles.

* This work was done in collaboration with Myung Joon Han (SNU) and Taisuke Ozaki (RICS).