Method of manufacturing magnetoresistive element

A magnetoresistive element manufactured by a method and comprising a layered structure and a pair of electrodes allowing an electric current to flow through the layered structure in a thickness direction,

• the layered structure comprising:
• a cap layer;
• a magnetization pinned layer;
• a magnetization free layer provided between the cap layer and the magnetization pinned layer;
• a spacer layer provided between the magnetization pinned layer and the magnetization free layer;
• and
• a functional layer provided in the magnetization pinned layer, between the magnetization pinned layer and the spacer layer, between the spacer layer and the magnetization free layer, in the magnetization free layer, or between the magnetization free layer and the cap layer and comprising an oxide containing at least one element selected from the group consisting of Zn, In, Sn, and Cd and at least one element selected from the group consisting of Fe, Co, and Ni;
• the method comprising:
• forming a film comprising a base material of the functional layer;
• performing an oxidation treatment on the film using a gas containing oxygen in a form of at least one selected from the group consisting of molecule, ion, plasma and radical;
• and
• performing a reduction treatment using a reducing gas on the film after the oxidation treatment.