Synthesis, structure and magnetic properties ofβ-MnO ₂ nanorods

Abstract

We present synthesis, structure and magnetic properties of structurally well-ordered single-crystalline β-MnO₂nanorods of 50–100 nm diameter and several µm length. Thorough structural characterization shows that the basic β-MnO₂material is covered by a thin surface layer (∼2.5 nm) of α-Mn₂O₃phase with a reduced Mn valence that adds its own magnetic signal to the total magnetization of the β-MnO₂nanorods. 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-MnO₂and α-Mn₂O₃constituent phases and the soft ferromagnetism of the thin interface layer between these two phases.

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