Apparatus for recognizing spin valve head failure due to pin layer magnetic field offset

A storage apparatus provided with a plurality of heads each having a read head and a write head which have been integrated thereinto, said read head comprising a spin valve head having a multilayered structure including an antiferromagnetic layer, a pin layer, a nonmagnetic layer and a free layer, said spin valve head electrically reading record information from a variation in the magnetic reluctance in response to a record magnetic field of a medium applied in the form of an external magnetic field with a sense current being allowed to flow therethrough in the interference direction causing a magnetic field opposite to the magnetic field in said pin layer, said storage apparatus comprising:

• a pin layer magnetic field offset judgment unit which, when there is judged a predetermined abnormality attributable to a magnetic field offset in said pin layer of said spin valve head, inverts the direction of said sense current and consequently if said predetermined abnormality is eliminated, judges that an offset of the magnetic field has occurred in said pin layer;
• and
• a recovery processing unit which, when said pin layer magnetic field offset judgment unit has judged that an offset of the magnetic field in said pin layer has occurred, allows a recovery from the abnormality arising from said offset in the magnetic field.