Magnetic sensor having CoFeBTa in pinned and free layer structures
A magnetic read sensor having improved magnetic performance and robustness. The magnetic sensor includes a magnetic free layer and a magnetic pinned layer structure. The magnetic pinned layer structure includes first and second magnetic layers separated from one another by a non-magnetic coupling layer. The second magnetic layer of the magnetic pinned layer structure includes a layer of CoFeBTa, which prevents the diffusion of atoms and also promotes a desired BCC crystalline grain growth. The magnetic free layer structure can also include such a CoFeBTa layer for further prevention of atomic diffusion and further promotion of a desired BCC grain growth.
1. A magnetic read sensor, comprising:
a magnetic pinned layer structure including a first magnetic layer structure, a second magnetic layer structure and a non-magnetic coupling layer sandwiched between the first and second magnetic layer structures;
a magnetic free layer structure; and
a non-magnetic barrier layer sandwiched between the magnetic free layer structure and the magnetic pinned layer structure; wherein
the second magnetic layer structure of the pinned layer structure comprises first, second, third and fourth magnetic sub-layers, the first magnetic sub-layer consisting of Co and being located adjacent to the non-magnetic coupling layer, the second magnetic sub-layer comprising CoFeBTa and contacting the first magnetic sub-layer, the third magnetic sub-layer comprising CoFeB and contacting the second magnetic sub-layer and the fourth magnetic sub-layer contacting the third magnetic sub-layer and comprising CoFe.
2. The magnetic sensor as in claim 1 wherein the second magnetic layer structure of the magnetic pinned layer structure is located adjacent to the non-magnetic barrier layer.
3. The magnetic sensor as in claim 1 wherein the free layer comprises first, second, third and fourth free sub-layers, the first free sub-layer being formed over the non-magnetic barrier layer and comprising CoFe, the second free sub-layer being formed over the first free sub-layer and comprising CoFeB, the third free sub-layer being formed over the second free sub-layer and comprising amorphous CoHf and the fourth free sub-layer being formed over the third free sub-layer and comprising NiFe X where X<10.
4. The magnetic sensor as in claim 1 wherein the second sub-layer has a thickness of 4-6 Angstroms.
5. The magnetic sensor as in claim 1 wherein the first sub-layer has a thickness of about 5 Angstroms, the second sub-layer has a thickness of about 5 Angstroms, the third sub-layer has a thickness of about 5 Angstroms and the fourth sub-layer has a thickness of about 4.5 Angstroms.
6. The magnetic sensor as in claim 1 wherein the layer of CoFeBTa has a concentration of (Co 40 Fe 40 B 20 ) l00-X Ta X where X is 4-10 atomic percent.
7. The magnetic sensor as in claim 1 wherein the layer of CoFeBTa has a concentration of (Co 60 Fe 20 B 20 ) l00-X Ta X where X is 4-10 atomic percent.
8. The magnetic sensor as in claim 1 wherein the layer of CoFeBTa has a concentration of CoFe X B Y Ta Z , where X is no greater than 60 atomic percent, Y is no greater than 30 atomic percent and Z is not greater than 15 atomic percent.
9. A magnetic sensor as in claim 1 wherein the magnetic free layer structure includes a layer of CoFeBTa.
10. A magnetic sensor as in claim 1 wherein the magnetic free layer structure includes first, second, third and fourth magnetic free sub-layers, the first magnetic free sub-layer being located adjacent to the non-magnetic barrier layer, the second magnetic free sub-layer contacting the first magnetic free sub-layer, the third magnetic free sub-layer contacting the second magnetic free sub-layer and the fourth magnetic free sub-layer contacting the third magnetic free sub-layer, wherein the third magnetic free sub-layer comprises CoFeBTa.
11. A magnetic sensor as in claim 1 wherein the magnetic free layer structure includes first, second, third and fourth magnetic free sub-layers, the first magnetic free sub-layer being located adjacent to the non-magnetic barrier layer, the second magnetic free sub-layer contacting the first magnetic free sub-layer, the third magnetic free sub-layer contacting the second magnetic free sub-layer and the fourth magnetic free sub-layer contacting the third magnetic free sub-layer, wherein the first magnetic free sub-layer comprises CoFe, the second magnetic free sub-layer comprises CoFeB, the third magnetic free sub-layer comprises CoFeBTa and the fourth magnetic free sub-layer comprises NiFe.
12. The magnetic sensor as in claim 9 wherein the layer of CoFeBTa in the magnetic pinned layer structure has a concentration of (Co 40 Fe 40 B 20 ) 100-X Ta X where 4<X<10 atomic percent, and the layer of CoFeBTa in the free layer structure has a concentration of (Co 76 Fe 4 B 20 ) (100-X) Ta (X) where 4<X<10 atomic percent.
13. The magnetic sensor as in claim 9 wherein the layer of CoFeBTa in the magnetic pinned layer structure has a concentration of (Co 60 Fe 20 B 20 ) (100-X) Ta (X) where 4<X<10 atomic percent, and the layer of CoFeBTa in the free layer structure has a concentration of (Co 76 Fe 4 B 20 ) (100-X) Ta (X) where 4<X<10 atomic percent.
14. The magnetic sensor as in claim 9 wherein the layer of CoFeBTa in the magnetic free layer structure has a concentration of CoFe X B Y Ta Z , where X is no greater than 10 atomic percent, Y is no greater than 25 atomic percent and Z is not greater than 10 atomic percent.
15. A magnetic data recording system, comprising:
a magnetic media;
an actuator;
a slider connected with the actuator for movement adjacent to a surface of the magnetic media; and
a magnetic read sensor formed on the slider, the magnetic read sensor further comprising:
a magnetic pinned layer structure including first and second magnetic layer structures and a non-magnetic coupling layer sandwiched between the first and second magnetic layer structures;
a magnetic free layer structure; and
a non-magnetic barrier layer sandwiched between the magnetic free layer structure and the magnetic pinned layer structure; wherein
the second magnetic layer structure of the pinned layer structure comprises first, second, third and fourth magnetic sub-layers, the first magnetic sub-layer consisting of Co and being located adjacent to the non-magnetic coupling layer, the second magnetic sub-layer comprising CoFeBTa and contacting the first magnetic sub-layer, the third magnetic sub-layer comprising CoFeB and contacting the second magnetic sub-layer and the fourth magnetic sub-layer contacting the third magnetic sub-layer and comprising CoFe.
16. The magnetic data recording system as in claim 15 , wherein the magnetic free layer structure includes a layer of CoFeBTa.