金属−フッ化物系ナノグラニュラー薄膜のトンネル型巨大磁気抵抗効果

抄録

The properties and structure of (Fe, Co)-Mg-F films, prepared by a tandem deposition method using rf sputtering apparatus, were studied. These films show granular-type TMR properties, and the MR ratio at 10 kOe of 42 vol.% Fe-Mg-F film is 7.8%, which is about twice large as that of Fe-Al-O film. The ρ values of the (Fe, Co)-Mg-F films are 10²-10⁴ times larger than that of (Fe, Co)-Al-O films. (Fe, Co)-Mg-F films have a nano-granular structure composed of metallic granules with a diameter of 2-3 nm and thin insulator boundaries; this structure is almost the same as that of (Fe, Co)-Al-O and other metal-oxide nano-granular TMR films. However, the insulator boundaries of (Fe, Co)-Mg-F films are formed from crystalline phase, while the structure of the boundary is amorphous phase in the case of metal-oxide-type nano-granular films.