Abstract: A magnetic head that reads information of a magnetic recording medium is provided. The magnetic head according to one embodiment includes: an MR element, formed with multilayer films, of which an electrical resistance changes according to an external magnetic field; a first shield layer that is disposed on a lower side in an lamination direction of the MR element; a second shield layer that is disposed on an upper side in the lamination direction of the MR element, and that applies voltage to the MR element together with the first shield layer; and side shield layers that are disposed on both sides of the MR element in a truck width direction. The side shield layers include soft magnetic layers and hard magnetic layers magnetized in a predetermined direction.

Abstract: According to one embodiment, a magneto-resistance effect device includes: a multilayer structure having 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; a function layer which is 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, the function layer having oxide containing at least one element selected from Zn, In, Sn and Cd, and at least one element selected from Fe, Co and Ni; and a pair of electrodes for applying a current perpendicularly to a film plane of the multilayer structure.

Abstract: Provided is a differential type reproduction head which can obtain a preferable bit error rate without causing a baseline shift even when two magnetoresistive elements have different maximum resistance change amounts. The differential type reproduction head has a layered structure formed by a first magnetoresistive element having a first free layer, a differential gap layer, and a second magnetoresistive element having a second free layer. When DR1 and DR2 are the maximum resistance change amounts of the first magnetoresistive element and the second magnetoresistive element, respectively, HB1 is a magnetic domain control field applied to the first free layer, and HB2 is a magnetic domain control field applied to the second free layer, the following relationships are satisfied: HB1>HB2 when DR1>DR2; HB2>HB1 when DR2>DR1.