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We present a report on the nanopatterning of an epitaxial ultrathin film of Fe3O4 with room-temperature (ferri)magnetism using atomic force microscopy (AFM). Fe3O4 thin films with atomically flat surfaces were grown using laser molecular-beam epitaxy on a MgAl2O4(111) single-crystal substrate. (Nanowire) were constructed on Fe3O4 thin film by applying an electric field between an AFM conductive tip and the surface of the film. The minimum width and height in the resulting nanowire are 48nm and 2nm, respectively. The patterned region of the Fe3O4 film surface possesses a resistance which is 105 times higher than the unpatterned region. Furthermore, magnetic force microscopy measurements also revealed that magnetization of the patterned region is strongly suppressed.

By atomic force microscopy (AFM), we have realized nanolithography and changed the physical properties within a desired nanosized region on Nb-doped SrTiO3 single-crystal substrate. Importantly, a considerable relaxation of these written patterns was observed directly, which evidently indicates that a significant chemical transport occurs during and after the AFM lithography. Furthermore, we found that defects introduced by Ar bombardment can stabilize these patterns, which is quite effective for the application of AFM lithography in perovskite oxides.

Atomic force microscopy (AFM) lithography has been performed in La0.8Ba0.2MnO3 (LBMO) films. Unexpectedly, controllable nano-sized patterns can be obtained with an excellent reproducibility under a negative sample bias rather than a positive one, which is completely different from doped SrTiO3 and high TC superconductors, though they are of similar perovskite structure. The size of AFM lithography patterns can be controlled well by the sample bias and the selection of tips. Compared to the non-patterned region, AFM lithography patterns exhibit different mechanical, electrical, even possible magnetic properties. Moreover, a simple wet etching can transfer AFM lithography patterns into nano-grooves with a high etching selectivity and without destroying the physical properties of LBMO thin films. It is expected that various spintronic nano-devices will be fabricated with perovskite manganites by AFM lithography and etching techniques.