Spin valve transistor using a magnetic tunnel junction

A magnetic read/write head, comprising:

• a write head including:
• at least one coil layer and an insulation stack, the coil layer being embedded in the insulation stack;
• first and second pole piece layers connected at a back gap and having pole tips with edges forming a portion of an air bearing surface (ABS);
• the insulation stack being sandwiched between the first and second pole piece layers;
• and
• a write gap layer sandwiched between the pole tips of the first and second pole piece layers and forming a portion of the ABS;
• a read head including:
• a spin valve transistor sensor, first and second shield layers and a common electrode, the spin valve transistor sensor being sandwiched between the first and second shield layers, the spin valve transistor sensor including:
• an emitter element including an antiferromagnetic layer, a first tunnel barrier layer and a ferromagnetic pinned layer, said ferromagnetic pinned layer located between the antiferromagnetic layer and the first tunnel barrier layer;
• a collector element including a second tunnel barrier layer and a ferromagnetic free layer adjacent to said second tunnel barrier layer;
• and
• a base element disposed between said emitter element and said collector element, a back edge of the base element connected to the common electrode, said base element being a nonmagnetic metal layer located between the first and second tunnel barrier layers;
• and
• an insulation layer disposed between the second shield layer of the read head and the first pole piece layer of the write head.

A disk drive system comprising:

• a magnetic recording disk;
• a magnetic read/write head for magnetically recording data on the magnetic recording disk and for sensing magnetically recorded data on the magnetic recording disk, said magnetic read/write head comprising:
• a write head including:
• at least one coil layer and an insulation stack, the coil layer being embedded in the insulation stack;
• first and second pole piece layers connected at a back gap and having pole tips with edges forming a portion of an air bearing surface (ABS);
• the insulation stack being sandwiched between the first and second pole piece layers;
• and
• a write gap layer sandwiched between the pole tips of the first and second pole piece layers and forming a portion of the ABS;
• a read head including:
• a spin valve transistor sensor, first and second shield layers and a common electrode, the spin valve transistor sensor being sandwiched between the first and second shield layers, the spin valve transistor sensor including:
• an emitter element including an antiferromagnetic layer, a first tunnel barrier layer and a ferromagnetic pinned layer, said ferromagnetic pinned layer located between the antiferromagnetic layer and the first tunnel barrier layer;
• a collector element;
• and
• a base element comprising a free ferromagnetic layer disposed between said collector element and the first tunnel barrier layer of said emitter element, a back edge of said base element connected to the common electrode;
• and
• an insulation layer disposed between the second shield layer of the read head and the first pole piece layer of the write head;
• an actuator for moving said magnetic read/write head across the magnetic disk so that the read/write head may access different regions of the magnetic recording disk;
• and
• a recording channel coupled electrically to the write head for magnetically recording data on the magnetic recording disk and to the spin valve transistor sensor of the read head for detecting changes in resistance of the spin valve transistor sensor caused by rotation of the magnetization axis of the ferromagnetic free layer relative to the fixed magnetizations of the ferromagnetic layer in response to magnetic fields from the magnetically recorded data.