A magnetoresistance effect element comprises 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; and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film, The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer. Alternatively, the concentration of oxygen in the first layer may have a two-dimensional fluctuation, and 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 % may be provided in the first layer.
A magnetoresistive element has a magnetization pinned layer a magnetization direction of which is substantially pinned in one direction, a magnetization free layer a magnetization direction of which varies depending on an external field, and a spacer layer including an insulating layer provided between the magnetization pinned layer and the magnetization free layer and current paths penetrating the insulating layer, the magnetization pinned layer or magnetization free layer located under the spacer layer comprising crystal grains separated by grain boundaries extending across a thickness thereof, in which, supposing that an in-plane position of one end of each of the crystal grains is set to 0 and an in-plane position of a grain boundary adjacent to the other end of the crystal grain is set to 100, the current path corresponding the crystal grain is formed on a region in a range between 20 and 80 of the in-plane position.
