Spin valve sensor with free layer structure having a cobalt niobium (CoNb) or cobalt niobium hafnium (CoNbHf) layer

A magnetic head assembly having an air bearing surface (ABS), comprising:

• a write head including:
• ferromagnetic first and second pole piece layers that have a yoke portion located between a pole tip portion and a back gap portion;
• a nonmagnetic write gap layer located between the pole tip portions of the first and second pole piece layers;
• an insulation stack with at least one coil layer embedded therein located between the yoke portions of the first and second pole piece layers;
• and
• the first and second pole piece layers being connected at their back gap portions;
• and
• a read head including:
• a spin valve sensor;
• nonmagnetic electrically nonconductive first and second read gap layers;
• the spin valve sensor being located between the first and second read gap layers;
• a ferromagnetic first shield layer;
• and
• the first and second gap layers being located between the first shield layer and the first pole piece layer;
• and
• the spin valve sensor including:
• a ferromagnetic pinned layer structure that has a magnetic moment;
• a pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• a free layer structure;
• a nonmagnetic conductive spacer layer located between the free layer structure and the pinned layer structure;
• the free layer structure including:
• a first free layer composed of cobalt or cobalt iron that interfaces the spacer layer;
• a second free layer composed of cobalt niobium or cobalt niobium hafnium wherein the cobalt is at least 90%;
• and the second free layer having a negative magnetostriction which at least partially counterbalances a positive magnetostriction of a remainder of the free layer structure.

A magnetic disk drive including at least one magnetic head assembly that has an air bearing surface (ABS) and that includes a write head and a read head, comprising:

• a write head including:
• ferromagnetic first and second pole piece layers that have a yoke portion located between a pole tip portion and a back gap portion;
• a nonmagnetic write gap layer located between the pole tip portions of the first and second pole piece layers;
• an insulation stack with at least one coil layer embedded therein located between the yoke portions of the first and second pole piece layers;
• and
• the first and second pole piece layers being connected at their back gap portions;
• and
• a read head including:
• a spin valve sensor;
• nonmagnetic electrically nonconductive first and second read gap layers;
• the spin valve sensor being located between the first and second read gap layers;
• a ferromagnetic first shield layer;
• and
• the first and second read gap layers being located between the first shield layer and the first pole piece layer;
• and
• the spin valve sensor including:
• a ferromagnetic pinned layer structure that has a magnetic moment;
• a pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• a free layer structure;
• a nonmagnetic electrically conductive spacer layer located between the free layer structure and the pinned layer structure;
• the free layer structure including:
• a first free layer composed of cobalt or cobalt iron that interfaces the spacer layer;
• a second free layer composed of cobalt niobium or cobalt niobium hafnium wherein the cobalt is at least 90%;
• and the second free layer being formed with a negative magnetostriction which at least partially counterbalances a positive magnetostriction of a remainder of the free layer structure.
• a housing;
• a magnetic disk rotatably supported in the housing;
• a support mounted in the housing for supporting the magnetic head assembly with said ABS facing the magnetic disk so that the magnetic head assembly is in a transducing relationship with the magnetic disk;
• a spindle motor for rotating the magnetic disk;
• an actuator positioning means connected to the support for moving the magnetic head assembly to multiple positions with respect to said magnetic disk;
• and
• a processor connected to the magnetic head assembly, to the spindle motor and to the actuator for exchanging signals with the magnetic head assembly, for controlling movement of the magnetic disk and for controlling the position of the magnetic head assembly.

A method of making a magnetic read head which has an air bearing surface (ABS), comprising the steps of:

• a making a spin valve sensor comprising the steps of:
• forming a ferromagnetic pinned layer structure that has a magnetic moment;
• forming a pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• forming a free layer structure;
• forming a nonmagnetic electrically conductive spacer layer between the free layer structure and the pinned layer structure;
• the free layer structure including:
• a first free layer composed of cobalt or cobalt iron that interfaces the spacer layer;
• a second free layer composed of cobalt niobium or cobalt niobium hafhium wherein the cobalt is at least 90%;
• and the second free layer being formed with a negative magnetostriction which at least partially counterbalances a positive magnetostriction of a remainder of the free layer structure.

A method of making magnetic head assembly that has an air bearing surface (ABS), comprising the steps of:

• making a write head including the steps of:
• forming ferromagnetic first and second pole piece layers in pole tip, yoke and back gap regions wherein the yoke region is located between the pole tip and back gap regions;
• forming a nonmagnetic electrically nonconductive write gap layer between the first and second pole piece layers in the pole tip region;
• forming an insulation stack with at least one coil layer embedded therein between the first and second pole piece layers in the yoke region;
• and
• connecting the first and pole piece layers at said back gap region;
• and
• making a read head including the steps of:
• forming nonmagnetic electrically nonconductive first and second read gap layers;
• forming a spin valve sensor between the first and second read gap layers;
• forming the first and second read gap layers between the first shield layer and the first pole piece layer;
• and
• a making of the spin valve sensor comprising the steps of:
• forming a ferromagnetic pinned layer structure that has a magnetic moment;
• forming a pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• forming a free layer;
• forming a nonmagnetic electrically conductive spacer layer between the free layer and the pinned layer structure;
• the free layer structure including:
• a first free layer composed of cobalt or cobalt iron that interfaces the spacer layer;
• a second free layer composed of cobalt niobium or cobalt niobium hafnium wherein the cobalt is at least 90%;
• and the second free layer being formed with a negative magnetostriction which at least partially counterbalances a positive magnetostriction of a remainder of the free layer structure.