Ferromagnetic ultra-small tunnel junction devices fabricated by scanning probe microscope (SPM) local oxidation

A novel lithography technique for fabricating ferromagnetic metal/insulator/ferromagnetic metal (FM/I/FM)-based nanoscale devices was investigated using a scanning probe microscope (SPM) local oxidation process. This technique was applied to the surface modification of Ni thin films. Planar-type Ni/Ni oxide/Ni-based diodes and ferromagnetic single-electron transistor (FMSET) structures were fabricated by SPM local oxidation. Ni-based diodes clearly showed nonlinear current-voltage (I-V) characteristics, and capacitively coupled FMSET structures with a Ni-based double ferromagnetic tunnel junction exhibited Coulomb blockade effects.