Patent ID: 7145754

Claim:
A magnetoresistance effect element comprising: a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer, the nonmagnetic intermediate layer having a first layer made of an oxide, a concentration of oxygen in the first layer having a two-dimensional fluctuation, the first layer having a first region where the concentration of oxygen is equal to or higher than 40 atomic % and a second region where the concentration of oxygen is equal to or lower than 35 atomic %; and a pair of electrodes electrically coupled to the magnetoresistance effect film and configured to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film, an ohmic characteristic being obtained when the sense current passes the first layer, the first region including a first element except oxygen, the second region including a second element except oxygen, the second element being different from the first element, and the nonmagnetic intermediate layer further having a second layer made of a non-magnetic metal.