Anomalous magnetic properties of Fe3O4 nanostructures on GaAs substrate probed using X-ray magnetic circular dichroism

•Nano-tips of Fe3O4 are grown on GaAs substrate.•XMCD shows its anomalous magnetic moment due to orbital moment contribution.•They show reduced DOS at Fermi level compared to bulk.•They reveal characteristic Verwey transition at 115 K. We have studied the magnetic properties and electronic structure of 2 nm Fe3O4 film on GaAs substrates, which evolve in a nano-tip structure and compared it with 150 nm thick Fe3O4 film. Valence band studies reveal a drop in density of states at Fermi level for 2 nm film as compared to thicker film. XMCD studies divulge the unusual high magnetization value of ∼5.1 μB/FU in 2 nm film compared to 3.9 μB/FU observed for bulk Fe3O4 or thicker Fe3O4 films. The excess moment is shown to be due to orbital moment contribution.