Magnetic properties of CoO nanoparticles

The magnetic circular X-ray dichroism (MCXD) of CoO nanoparticles was measu red at low temperatures and in high magnetic fields. The particles show a s uperparamagnetic behaviour at room temperature, and a large orbital contrib ution to the magnetic moment at low temperatures was observed. This enhance ment of orbital magnetism is largely determined by the contribution of the surface atoms. The larger spin-orbit coupling of the electrons of the surfa ce atoms of the particle can cause a change in magnetic ordering in the cor e of the particles.