Development of Observation Method of Fine Magnetic Domains using Spin Polarized Electron Detection Probe

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In this research, it is extremely important to develop the probe needle to detect spin polarization of electrons in the magnetic domains in magnetic materials, such as magnetic thin film media used in magnetic recording system especially in perpendicular magnetic recording system. These probe needle were fabricated using photo lithography technique. Firstly, substrates were coated with photoresist (OFPR) layrs and sputtered-Al films were deposited on it. Micro holes with its diameter around several mum were fabricated in the Al layrs by also photolithography technique. Photoresist under the hole were eliminated by the plasma ashing method using Oxygen mixture plasma. The probe will be formed when the sputtered particles through the hole are deposited on the substrate. We clarified that the relationship between aspect ratio, which defined as the diameter of the hole and the thickness of the photoresist layr, and the probe profiles by using Monte-Carlo simulation technique. Small aspect ratio resulted in the sharp profile of the deposited probe needles. Spin tunneling phenomena is one of the key point of this research, because the probe has to detect the spin polarization of the electrons which comes from the magnetic domains in the objective materials to the probe needle through an tunneling effect. In order to clarify the spin tunneling effect, spin valve devices composed of Ni-Fe/Si_3N_4/Ni-Fe sandwiched layrs with Fe-Mn antiferromagnetic bias layrs. It was succesfully observed the spin tunneling spin valve characteristic in these devices.