STRUCTURE AND MAGNETIC PROPERTIES OF MANGANESE OXIDE NANOPARTICLES PREPARED BY ARC SUBLIMATION

Abstract

Manganese oxide nanoparticles with narrow size distribution were prepared in large scale by arc sublimation of bulk MnO . Although MnO is antiferromagnetic, the as-prepared manganese oxide nanoparticles exhibit ferromagnetic behaviors with coercivity and exchange bias up to 417,065 A/m and 162,099 A/m at 5 K, respectively. We attribute these anomalous magnetic properties to the presence of ferrimagnetic Mn 3 O 4, uncompensated surface spins and their coupling to the antiferromagnetic MnO .