Magnetization Reversal in Different Magnetic Thin Films Studied Using a Magnetic Actuator

Abstract

We propose a novel method for observing the magnetization reversal of ferromagnetic thin film; the novel method is to observe the deflection of a magnetic actuator under various magnetic fields. However, they are necessary that the magnetic actuator is bent using a ferromagnetic thin film and that the deflection of the magnetic actuator is obvious enough to study the magnetization reversal of the ferromagnetic thin film. The magnetic actuator consisting of a 76×0.75×0.3 µm3 silicon oxide microcantilever and a 75×9×0.3 µm3 silicon oxide plate deposited on a ferromagnetic multilayer thin film is successfully fabricated using electron beam lithography and electron beam evaporation, and placed in various magnetic fields to observe its flexure. In this study, three shapes of magnetic element are designed: 60×1×0.09 µm3, 60×3×0.09 µm3, and 60×6×0.09 µm3. In the sweep-down process, the magnetization of the 60×6×0.09 µm3 ferromagnetic thin film is reversed at -147 G; the magnetization of the 60×3×0.09 µm3 ferromagnetic thin film is reversed at -313 G; and the magnetization of the 60×6×0.09 µm3 ferromagnetic thin film is reversed at -643 G. The study is useful for applications of the magnetic actuator.