Study on magnetoresistance for trilayer with Fe_3O_4 film

摘要

High quality Fe_3O_4 thin film was synthesized by the magnetron sputtering method using Ar-H_2 gas. Giant magneto resistance of the trilayer using Fe_3O_4 was investigated, where the observed MR ratio was less than 1%. A phenomenological calculation was made to make the origin of the small MR ratio clear, using a parallel current model assuming five passes. It is concluded that the non-magnetic layer surrounded by two magnetic layers is necessary to have the same order resistivity and similar thickness with Fe_3O_4 layer in order to obtain the large MR ratio for the trilayer using