Co-Fe supermalloy free layer for magnetic tunnel junction heads

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 magnet tunnel junction (MTJ) sensor, first and second gap layers, and first and second shield layers, the MTJ sensor being sandwiched between the first and second gap layers and the first and second gap layers being sandwiched between the first and second shield layers;
• the MTJ sensor including:
• an antiferromagnetic (AFM) layer;
• a tunnel barrier layer;
• a pinned layer disposed between the AFM layer and the tunnel junction layer;
• and
• a ferromagnetic free layer formed on the tunnel junction layer, said free layer comprising:
• a first sublayer formed on the tunnel junction layer;
• a second sublayer formed on the first sublayer, wherein said second sublayer is made of supermalloy (Ni—Fe—Mo) having a thickness in the range of 60-80 Å;
• 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 magnetic tunnel junction (MTJ) sensor, first and second gap layers, and first and second shield layers, the MTJ sensor being sandwiched between the first and second gap layers and the first and second gap layers being sandwiched between the first and second shield layers;
• the MTJ sensor including:
• an antiferromagnetic (AFM) layer;
• a tunnel junction layer;
• a pinned layer disposed between the AFM layer and the tunnel junction layer;
• and
• a ferromagnetic free layer formed on the tunnel junction layer, said free layer comprising:
• a first sublayer formed on the tunnel junction layer;
• and
• a second sublayer formed on the first sublayer, wherein said second sublayer is made of supermalloy (Ni—Fe—Mo) having a thickness in the range of 60-80 Å;
• 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 MTJ sensor of the read head for detecting changes in resistance of the MTJ sensor caused by rotation of the magnetization axis of the free ferromagnetic layer relative to the fixed magnetization of the pinned layer in response to magnetic fields from the magnetically recorded data.