Magnetoresistance effect element, magnetic memory, and method for manufacturing magnetoresistance effect element

A magnetoresistance effect element, comprising:

• a first magnetic layer of which a magnetization direction is a direction perpendicular to a film surface;
• a first non-magnetic layer which is provided adjacent to the first magnetic layer;
• a second magnetic layer which is provided adjacent to the first magnetic layer on an opposite side to the first non-magnetic layer and of which a magnetization direction is a direction perpendicular to the film surface;
• a third magnetic layer which is provided adjacent to the second magnetic layer on an opposite side to the first magnetic layer and of which a magnetization direction is a direction perpendicular to the film surface;
• and
• a second non-magnetic layer which is provided adjacent to the third magnetic layer on an opposite side to the second magnetic layer, wherein
• the first magnetic layer includes at least Fe, an Fe composition in the first magnetic layer being 50 at % or higher with respect to a sum total of atomic fractions of magnetic elements in the first magnetic layer, a magnetization direction of the first magnetic layer being oriented in a perpendicular direction with respect to the film surface due to interfacial perpendicular magnetic anisotropy on an interface with the first non-magnetic layer,
• the third magnetic layer includes at least Fe, an Fe composition in the third magnetic layer being 50 at % or higher with respect to a sum total of atomic fractions of magnetic elements in the third magnetic layer, a magnetization direction of the third magnetic layer being oriented in a perpendicular direction with respect to the film surface due to interfacial perpendicular magnetic anisotropy on an interface with the second non-magnetic layer,
• an interfacial magnetic anisotropy energy density Ki on an interface between the first non-magnetic layer and the first magnetic layer is higher than an interfacial magnetic anisotropy energy density Ki on an interface between the first non-magnetic layer and the second magnetic layer if the first non-magnetic layer and the second magnetic layer were directly joined to each other,
• an interfacial magnetic anisotropy energy density Ki on an interface between the second non-magnetic layer and the third magnetic layer is higher than an interfacial magnetic anisotropy energy density Ki on an interface between the second non-magnetic layer and the second magnetic layer if the second non-magnetic layer and the second magnetic layer were directly joined to each other, and
• a saturation magnetization Ms of the second magnetic layer is lower than a saturation magnetization Ms of the first magnetic layer and a saturation magnetization Ms of the third magnetic layer.

A method for manufacturing a magnetoresistance effect element by stacking, in the following order:

• a first non-magnetic layer;
• a first magnetic layer which is provided adjacent to the first non-magnetic layer and of which a magnetization direction is a direction perpendicular to a film surface, the first magnetic layer including at least Fe, an Fe composition in the first magnetic layer being 50 at % or higher with respect to a sum total of atomic fractions of magnetic elements in the first magnetic layer;
• a first non-magnetic insertion layer which is provided adjacent to the first magnetic layer on an opposite side to the first non-magnetic layer, the first non-magnetic insertion layer being made of a first metal;
• a second magnetic layer which is provided adjacent to the first non-magnetic insertion layer on an opposite side to the first magnetic layer and of which a magnetization direction is a direction perpendicular to the film surface, the second magnetic layer including at least one 3d ferromagnetic transition metal element consisting of one or more among the group of Co, Fe, Ni, and Mn, an Fe composition in the second magnetic layer being 50 at % or lower with respect to a sum total of atomic fractions of magnetic elements in the second magnetic layer;
• a second non-magnetic insertion layer which is provided adjacent to the second magnetic layer on an opposite side to the first non-magnetic insertion layer, the second non-magnetic insertion layer being made of a second metal;
• a third magnetic layer which is provided adjacent to the second non-magnetic insertion layer on an opposite side to the second magnetic layer and of which a magnetization direction is a direction perpendicular to the film surface, the third magnetic layer including at least Fe, an Fe composition in the third magnetic layer being 50 at % or higher with respect to a sum total of atomic fractions of magnetic elements in the third magnetic layer;
• and
• a second non-magnetic layer which is provided adjacent to the third magnetic layer on an opposite side to the second non-magnetic insertion layer, wherein
• the first non-magnetic insertion layer is formed using a first sputtering gas,
• the second non-magnetic insertion layer is formed using a second sputtering gas, and
• a first MT/MG ratio being a ratio of a mass number MT of the first metal of the first non-magnetic insertion layer to a mass number MG of the first sputtering gas is smaller than a second MT/MG ratio being a ratio of a mass number MT of the second metal of the second non-magnetic insertion layer to a mass number MG of the second sputtering gas.