Patent ID: 7842334

Claim:
A method for manufacturing a magnetic sensor that comprises: a single substrate; a first giant magnetoresistive element disposed on the substrate and formed of a single-layer-pinned spin-valve film comprising a single-layer-pinned fixed magnetization layer including a pinning layer and a single ferromagnetic layer, a free layer whose magnetization direction changes in response to an external magnetic field, and a spacer layer made of a nonmagnetic conductive material, disposed between the ferromagnetic layer and the free layer, wherein the magnetization of the ferromagnetic layer is fixed in a first direction by the pinning layer, so that the ferromagnetic layer serves as a pinned layer; and a second giant magnetoresistive element disposed on the substrate and formed of a plural-layer-pinned spin-valve film comprising a plural-layer-pinned fixed magnetization layer including a first ferromagnetic layer, an exchange coupling layer adjoining the first ferromagnetic layer, a second ferromagnetic layer adjoining the exchange coupling layer, and a pinning layer adjoining the second ferromagnetic layer, a free layer whose magnetization direction changes in response to an external magnetic field, and a spacer layer made of a nonmagnetic conductive material disposed between the first ferromagnetic layer and the free layer, wherein the magnetization direction of the second ferromagnetic layer is fixed by the pinning layer and the magnetization direction of the first ferromagnetic layer is fixed in a second direction antiparallel to the first direction by exchange coupling of the first ferromagnetic layer and the second ferromagnetic layer with the exchange coupling layer therebetween, so that the first ferromagnetic layer serves as a pinned layer, the method comprising: a film forming step of forming a film intended to act as the first giant magnetoresistive element and a film intended to act as the second giant magnetoresistive element on the substrate; and a magnetic field heat treatment step of applying a magnetic field oriented in a single direction to the films formed on the substrate at a high-temperature to fix the magnetization direction of each pinned layer.