Method for preparing FePt media at low ordering temperature and fabrication of exchange coupled composite media and gradient anisotropy media for magnetic recording
View Patent ↗A method includes: constructing a multilayer structure including a first layer of Pt, a first layer of A1 phase FePt on the first layer of Pt, and a second layer of Pt on the layer of FePt, and annealing the multilayer structure to convert the A1 phase FePt to L1 o phase FePt.
1. A method comprising:
constructing a multilayer structure including a first layer of Pt, a first layer of A1 phase FePt on the first layer of Pt, and a second layer of Pt on the layer of FePt; annealing the multilayer structure to convert the A1 phase FePt to L1 o phase FePt;
removing the second layer of Pt; and
depositing a layer of magnetically soft material on the L1 o phase FePt.
2. The method of claim 1 , wherein the annealing step is performed at about 300° C.
3. The method of claim 1 , wherein the A1 phase FePt is Fe rich and comprises:
Fe 50+x ,Pt 50-x , where x is larger than 5 but less than 30.
4. The method of claim 1 , wherein the multilayer structure further comprises:
grain isolation material.
5. The method of claim 1 , wherein:
the first layer of Pt has a thickness in the range of from about 0.5 nm to about 2 nm;
the first layer of A1 phase FePt on the first layer of Pt has a thickness in the range of from about 2 nm to about 10 nm; and
the second layer of Pt on the layer of FePt has a thickness in the range of from about 0 nm to about 5 nm.
6. The method of claim 1 , wherein the multilayer structure is on a substrate comprising one of:
glass, aluminum, or an aluminum alloy.
7. The method of claim 1 , wherein the multilayer structure is formed by physical vapor deposition.
8. The method of claim 1 , wherein the physical vapor deposition comprises one of:
magnetron sputtering, pulsed laser deposition, or ion beam deposition.
9. The method of claim 1 , wherein the annealing step is performed at a minimum annealing temperature in a range from about 200° C. to about 500° C.
10. A method comprising:
constructing a multilayer structure including a first layer of Pt, a first layer of A1 phase FePt on the first layer of Pt, and a second layer of Pt on the layer of FePt;
annealing the multilayer structure to convert the A1 phase FePt to L1 o phase FePt;
removing the second layer of Pt;
depositing an exchange control layer on the L1 o phase FePt; and
depositing a layer of magnetically soft material on the exchange control layer.
11. The method of claim 10 , wherein the exchange control layer comprises at least one of:
Pt, Pd, or a non-magnetic material.
12. The method of claim 10 , wherein the multilayer structure further comprises:
grain isolation material.
13. The method of claim 10 , wherein the annealing step is performed at about 300° C.
14. The method of claim 10 , wherein the A1 phase FePt is Fe rich and comprises:
Fe 50+x Pt 50-x , where x is larger than 5 but less than 30.
15. The method of claim 10 , wherein:
the first layer of Pt has a thickness in the range of from about 0.5 nm to about 2 nm;
the first layer of A1 phase FePt on the first layer of Pt has a thickness in the range of from about 2 nm to about 10 nm; and
the second layer of Pt on the layer of FePt has a thickness in the range of from about 0 nm to about 5 nm.
16. The method of claim 10 , wherein the multilayer structure is on a substrate comprising one of:
glass, aluminum, or an aluminum alloy.
17. The method of claim 10 , wherein the multilayer structure is formed by physical vapor deposition.
18. The method of claim 10 , wherein the physical vapor deposition comprises one of:
magnetron sputtering, pulsed laser deposition, or ion beam deposition.
19. The method of claim 10 , wherein the annealing step is performed at a minimum annealing temperature in a range from about 200° C. to about 500° C.