Synthesis, structure and magnetic properties ofβ-MnO(2)nanorods

We present synthesis, structure and magnetic properties of structurally well-ordered single-crystalline β-MnO(2)nanorods of 50–100 nm diameter and several µm length. Thorough structural characterization shows that the basic β-MnO(2)material is covered by a thin surface layer (∼2.5 nm) of α-Mn(2)O(3)phase with a reduced Mn valence that adds its own magnetic signal to the total magnetization of the β-MnO(2)nanorods. The relatively complicated temperature-dependent magnetism of the nanorods can be explained in terms of a superposition of bulk magnetic properties of spatially segregated β-MnO(2)and α-Mn(2)O(3)constituent phases and the soft ferromagnetism of the thin interface layer between these two phases.