Spin-valve magnetoresistive element and method for making the same

A spin-valve magnetoresistive element comprising:

• an antiferromagnetic layer;
• a first pinned magnetic layer in contact with the antiferromagnetic layer;
• a nonmagnetic interlayer;
• a second pinned magnetic layer, the nonmagnetic interlayer being disposed between the first pinned magnetic layer and the second pinned magnetic layer, the magnetization vector of the second pinned magnetic layer being aligned in a direction antiparallel to the magnetization vector of the first pinned magnetic layer;
• a nonmagnetic conductive layer in contact with the second pinned magnetic layer;
• a free magnetic layer in contact with the nonmagnetic conductive layer;
• longitudinal biasing layers;
• and
• a pair of lead layers;
• wherein, when the detecting current is supplied from the lead layers, the magnetization vector of the free magnetic layer is aligned in a direction intersecting the magnetization vector of the second pinned magnetic layer, and the magnetization vector of the free magnetic layer is tilted from the track width direction toward the magnetization vector of the second pinned magnetic layer.

A method for making a spin-valve magnetoresistive element comprising:

• forming a composite comprising an antiferromagnetic layer, a first pinned magnetic layer, a nonmagnetic interlayer, a second pinned magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer on a substrate, the free magnetic layer being formed while applying a first magnetic field in one of a first direction along a track width direction and a direction opposite to the first direction to impart uniaxial anisotropy in the track width direction to the free magnetic layer;
• first annealing of the composite at a first annealing temperature while applying a second magnetic field in one of a second direction tilted by an angle θ from the normal of the track width direction and a third direction opposite to the second direction to generate an exchange anisotropic magnetic field at the interface between the antiferromagnetic layer and the first pinned magnetic layer so as to pin the magnetization of the first pinned magnetic layer and the magnetization of the second pinned magnetic layer in directions which are tilted by the angle θ from the normal of the track width direction and which are antiparallel to each other;
• forming longitudinal biasing layers, for applying a biasing magnetic field to the free magnetic layer, on both sides of the laminate;
• second annealing of the laminate at a second annealing temperature while applying a third magnetic field to the free magnetic layer in one of the first direction and a direction opposite to the first direction to impart uniaxial anisotropy to the free magnetic layer;
• and
• applying a fourth magnetic field in a fourth direction opposite to the component in the track width direction of the magnetization vector of the second pinned magnetic layer to magnetize the longitudinal biasing layers.

A method for making a spin-valve magnetoresistive element comprising:

• forming a composite comprising an antiferromagnetic layer, a first pinned magnetic layer, a nonmagnetic interlayer, a second pinned magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer on a substrate, the free magnetic layer being formed while applying a first magnetic field in one of a first direction along a track width direction and a direction opposite to the first direction to impart uniaxial anisotropy in the track width direction to the free magnetic layer;
• first annealing of the composite at a first annealing temperature while applying a second magnetic field in a second direction orthogonal to the track width direction to generate an exchange anisotropic magnetic field at the interface between the antiferromagnetic layer and the first pinned magnetic layer so as to pin the magnetization of the first pinned magnetic layer and the magnetization of the second pinned magnetic layer in a direction orthogonal to the track width direction;
• forming longitudinal biasing layers, for applying a biasing magnetic field to the free magnetic layer, on both sides of the laminate;
• second annealing of the laminate at a second annealing temperature while applying a third magnetic field to the free magnetic layer in one of the first direction and a direction opposite to the first direction to impart uniaxial anisotropy to the free magnetic layer and to tilt by an angle θ from the normal of the track width direction the magnetization vector of the first pinned magnetic layer and the magnetization vector of the second pinned magnetic layer;
• and
• applying a fourth magnetic field in a fourth direction opposite to the component in the track width direction of the magnetization vector of the second pinned magnetic layer to magnetize the longitudinal biasing layers.

A method for making a spin-valve magnetoresistive element comprising:

• a composite forming step for forming a composite comprising an antiferromagnetic layer, a first pinned magnetic layer, a nonmagnetic interlayer, a second pinned magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer on a substrate, and for imparting uniaxial anisotropy in the track width direction to the free magnetic layer
• a first annealing step for pinning the magnetization of the first pinned magnetic layer and the magnetization of the second pinned magnetic layer in directions which are tilted from the normal of the track width direction and which are antiparallel to each other;
• a biasing layer forming step for forming longitudinal biasing layers;
• a second annealing step for imparting uniaxial anisotropy to the free magnetic layer;
• and
• a biasing layer magnetizing step for magnetizing the longitudinal biasing layers.

A method for making a spin-valve magnetoresistive element comprising:

• a composite forming step for imparting uniaxial anisotropy in the track width direction to the free magnetic layer;
• a first annealing step for pinning the magnetization of the first pinned magnetic layer and the magnetization of the second pinned magnetic layer in a direction orthogonal to the track width direction;
• a biasing layer forming step for forming longitudinal biasing layers;
• a second annealing step for imparting uniaxial anisotropy to the free magnetic layer and for tilting from the normal of the track width direction the magnetization vector of the first pinned magnetic layer and the magnetization vector of the second pinned magnetic layer;
• and
• a biasing layer magnetizing step for magnetizing the longitudinal biasing layers.