Current perpendicular to the planes (CPP) sensor with free layer stabilized by current field

A magnetic head assembly having a head surface for facing a magnetic medium comprising:

• first and second CPP sensors;
• each CPP sensor including a ferromagnetic free layer which has a magnetic moment that is oriented substantially parallel to the head surface and is free to rotate in response to a signal field from a magnetic medium;
• each free layer having major planes that are perpendicular to the head surface and a stripe height that extends normal to said head surface into the magnetic head assembly;
• a nonmagnetic electrically conductive bias layer located between the first and second CPP sensors with major planes parallel to the major planes of the free layer and extending in a direction away from the head surface into the head assembly beyond the stripe heights;
• ferromagnetic first and second shield layers;
• the first and second CPP sensors and the bias layer being located between the first and second shield layers;
• the first and second shield layers being electrically connected to the first and second CPP sensors respectively for conducting first and second currents respectively through the sensor perpendicular to the major planes of the free layers to the bias layer;
• and
• the bias layer being electrically connected to the first and second CPP sensors and sized so that the first and second currents can flow through the bias layer perpendicular to the head surface to cause a biasing field that biases the magnetic moments of the free layers antiparallel with respect to one another.

A method of making a magnetic head assembly having a head surface for facing a magnetic medium comprising the steps of:

• forming a CPP sensor having a plurality of layers wherein the layers have major planes that are perpendicular to the head surface and the layers have a stripe height that extends normal to said head surface into the magnetic head assembly;
• forming a first lead electrically connected to the sensor for conducting a current through the sensor perpendicular to said major planes of the layers and parallel to said head surface;
• forming a second lead extending from the stripe height into the head assembly;
• forming a nonmagnetic electrically conductive bias layer having major planes that are parallel to the major planes of the sensor and that is electrically connected to the sensor and the second lead and sizing it in width so that when the current flows through the bias layer parallel to the major planes of the bias layer and perpendicular to said head surface the CPP sensor is biased.

A method of making a magnetic head assembly having a head surface for facing a magnetic medium comprising the steps of:

• forming first and second CPP sensors;
• forming each CPP sensor with a ferromagnetic free layer which has a magnetic moment that is oriented substantially parallel to the head surface and is free to rotate in response to a signal field from a magnetic medium;
• forming each free layer with major planes that are perpendicular to the head surface and a stripe height that extends normal to said head surface into the magnetic head assembly;
• forming a nonmagnetic electrically conductive bias layer between the first and second CPP sensors with major planes parallel to the major planes of the free layer and extending in a direction away from the head surface into the head assembly beyond the stripe heights;
• forming ferromagnetic first and second shield layers;
• locating the first and second CPP sensors and the bias layer between the first and second shield layers;
• electrically connecting the first and second shield layers to the first and second CPP sensors respectively for conducting first and second currents respectively through the sensor perpendicular to the major planes of the free layers to the bias layer;
• and
• electrically connecting the bias layer to the first and second CPP sensors and sizing it so that the first and second currents can flow through the bias layer perpendicular to the head surface to cause a biasing field that biases the magnetic moments of the free layers antiparallel with respect to one another.