Magnetic domain structure of MnIr/NiFe bilayers patterned by focused ion beam

Summary form only given. One of the important issues for developing a magnetic random access memory (MRAM) is to understand the magnetic domain structure and the magnetization reversal in miniaturized magnetic elements. In this study, we have investigated the magnetic domain structures of NiFe and MnIr/NiFe elements patterned down to sub-micron scale by a focused ion beam (FIB). NiFe and MnIr/NiFe films were prepared by rf magnetron sputtering onto Si[100] substrates under a DC magnetic field of 80 Oe. The films were transferred to the FIB chamber without breaking the vacuum, and then etched by the irradiation of a 20 keV Ga/sup +/ focused ion beam. The topography and the domain structure of the micro-fabricated elements were measured by atomic force microscopy (AFM) and magnetic force microscopy (MFM), respectively.