Magnetoresistance effect device

A magnetoresistance effect device comprising:

• at least one magnetoresistance effect element including:
• a first magnetization free layer;
• a magnetization fixed layer or a second magnetization free layer;
• and
• a spacer layer sandwiched between the first magnetization free layer and the magnetization fixed layer or the second magnetization free layer;
• and
• a magnetic field applying unit configured to apply a magnetic field at least to the first magnetization free layer of the magnetoresistance effect element, wherein
• the magnetic field applying unit includes:
• a first ferromagnetic material having a protruding portion protruding from a first surface to the magnetoresistance effect element side in a stacking direction of the magnetoresistance effect element;
• a second ferromagnetic material sandwiching the magnetoresistance effect element together with the first ferromagnetic material;
• and
• a coil wound around the first ferromagnetic material,
• the first magnetization free layer of the magnetoresistance effect element includes a portion free of overlapping with at least one of a second surface of the protruding portion on the magnetoresistance effect element side in the stacking direction and a third surface of the second ferromagnetic material on the magnetoresistance effect element side in the stacking direction in a plan view when viewed in the stacking direction, and
• a center of gravity of the first magnetization free layer of the magnetoresistance effect element is positioned in a region connecting the second surface and the third surface.