IP Library Granted Patent US 10,803,896
Granted Patent B1
US 10,803,896 · App. 16/743,827 · Granted Oct 13, 2020

Data storage device using single-layer multi-level magnetic recording

Inventor: Aaron K. Mohl (Arvada, CO)
Assignee: Western Digital Technologies, Inc.
G11B5/68G11B5/09G11B5/62G11B2005/0018G11B2005/0021G11B2005/0024G11B2005/0034
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Quick Facts
Patent No.
US 10,803,896
App. No.
16/743,827
Granted
Oct 13, 2020
Kind
B1
Abstract

A data storage device is disclosed comprising a disk surface comprising a magnetic recording layer comprising a first magnetic material having a first coercivity intermixed with a second magnet material having a second coercivity higher than the first coercivity, and a head comprising a write coil configured to magnetize the magnetic recording layer in order to write data to the disk surface. The data is written to the disk surface by configuring the magnetic recording layer into one of at least three recording states, and the data is read from the disk surface by reading the magnetic recording layer using the head to generate a multi-level read signal, where each level of the read signal corresponds to one of the recording states.

Claims (56)

1. A data storage device comprising:

a disk surface comprising a magnetic recording layer comprising a first magnetic material having a first coercivity intermixed with a second magnet material having a second coercivity higher than the first coercivity;

a head comprising a write coil configured to magnetize the magnetic recording layer in order to write data to the disk surface; and

control circuitry configured to:

write the data to the disk surface by configuring the magnetic recording layer into one of at least three recording states;

read the data from the disk surface by reading the magnetic recording layer using the head to generate a multi-level read signal, where each level of the read signal corresponds to one of the recording states; and

detect the data from the multi-level read signal using an adjustable detector configured to account for a deviation in a ratio of the magnetic materials from a target ratio.

2. The data storage device as recited in claim 1 , wherein the target ratio of the first magnetic material to the second magnetic material is approximately 1:1.

3. The data storage device as recited in claim 1 , wherein the magnetic recording layer comprises a bit-patterned media composed of the first material.

4. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to write the data to the disk surface by applying an energy assist to the magnetic recording layer while applying a write current to the write coil.

5. The data storage device as recited in claim 4 , wherein the control circuitry is further configured to:

write the data to the disk surface by configuring the magnetic recording layer into one of at least a first recording state, a second recording state, or a third recording state;

apply a first non-zero energy assist to the magnetic recording layer and apply a non-zero write current to the write coil to configure the magnetic recording layer into the first recording state or the second recording state; and

apply a second non-zero energy assist to the magnetic recording layer and apply the non-zero write current to the write coil to configure the magnetic recording layer into the third recording state, wherein the second non-zero energy assist is less than the first non-zero energy assist.

6. The data storage device as recited in claim 5 , wherein the control circuitry is further configured to:

apply a first polarity non-zero write current to the write coil to configure the magnetic recording layer into the first recording state; and

apply a second polarity non-zero write current to the write coil to configure the magnetic recording layer into the second recording state, wherein the first polarity is opposite the second polarity.

7. The data storage device as recited in claim 5 , wherein the control circuitry is further configured to:

write the data to the disk surface by configuring the magnetic recording layer into one of at least the first recording state, the second recording state, the third recording state, or a fourth recording state; and

apply the first non-zero energy assist to the magnetic recording layer and apply a zero write current to the write coil to configure the magnetic recording layer into the fourth recording state.

8. The data storage device as recited in claim 7 , wherein the target ratio of the first magnetic material to the second magnetic material is within a range of 1.2:1 and 2:1.

9. The data storage device as recited in claim 7 , wherein the fourth recording state corresponds to a substantially zero level of the read signal.

10. The data storage device as recited in claim 1 , wherein:

the magnetic recording layer further comprises a third magnetic material having a third coercivity intermixed with the first magnetic material and the second magnet material, wherein the third coercivity is higher than the second coercivity; and

the control circuitry is further configured to write the data to the disk surface by configuring the magnetic recording layer into one of at least a first recording state, a second recording state, a third recording state, or a fourth recording state.

11. The data storage device as recited in claim 10 , wherein the control circuitry is further configured to:

write the data to the disk surface by applying an energy assist to the magnetic recording layer while applying a write current to the write coil;

apply a first non-zero energy assist to the magnetic recording layer and apply a non-zero write current to the write coil to configure the magnetic recording layer into the first recording state or the second recording state;

apply a second non-zero energy assist to the magnetic recording layer and apply the non-zero write current to the write coil to configure the magnetic recording layer into the third recording state, wherein the second non-zero energy assist is less than the first non-zero energy assist; and

apply a third non-zero energy assist to the magnetic recording layer and apply the non-zero write current to the write coil to configure the magnetic recording layer into the fourth recording state, wherein the third non-zero energy assist is less than the second non-zero energy assist.

12. The data storage device as recited in claim 11 , wherein the control circuitry is further configured to:

write the data to the disk surface by configuring the magnetic recording layer into one of at least the first recording state, the second recording state, the third recording state, the fourth recording state, or a fifth recording state; and

apply the first non-zero energy assist to the magnetic recording layer and apply a zero write current to the write coil to configure the magnetic recording layer into the fifth recording state.

13. A data storage device comprising:

a disk surface comprising a magnetic recording layer;

a head comprising a write coil and an energy assist element configured to generate an energy assist during write operations; and

control circuitry configured to:

write data to the disk surface by configuring the magnetic recording layer into one of at least a first recording state, a second recording state, or a third recording state;

apply a non-zero energy assist to the magnetic recording layer and apply a non-zero write current to the write coil to configure the magnetic recording layer into the first recording state or the second recording state; and

apply the non-zero energy assist to the magnetic recording layer and apply a zero write current to the write coil to configure the magnetic recording layer into the third recording state.

14. The data storage device as recited in claim 13 , wherein the control circuitry is further configured to:

apply a first polarity non-zero write current to the write coil to configure the magnetic recording layer into the first recording state; and

apply a second polarity non-zero write current to the write coil to configure the magnetic recording layer into the second recording state, wherein the first polarity is opposite the second polarity.

15. The data storage device as recited in claim 13 , wherein the control circuitry is further configured to:

read the data from the disk surface by reading the magnetic recording layer using the head to generate a multi-level read signal, where each level of the read signal corresponds to one of the recording states; and

the third recording state corresponds to a substantially zero level of the read signal.

16. A data storage device comprising:

a disk surface comprising a magnetic recording layer comprising a first magnetic material having a first coercivity intermixed with a second magnet material having a second coercivity higher than the first coercivity;

a means for writing data to the disk surface by configuring the magnetic recording layer into one of at least three recording states;

a means for reading the data from the disk surface by reading the magnetic recording layer to generate a multi-level read signal, where each level of the read signal corresponds to one of the recording states; and

a means for detecting the data from the multi-level read signal by accounting for a deviation in a ratio of the magnetic materials from a target ratio.

17. The data storage device as recited in claim 16 , wherein the target ratio of the first magnetic material to the second magnetic material is approximately 1:1.

18. The data storage device as recited in claim 16 , wherein the magnetic recording layer comprises a bit-patterned media composed of the first material.

19. The data storage device as recited in claim 16 , further comprising a means for writing the data to the disk surface by configuring the magnetic recording layer into one of at least a first recording state, a second recording state, or a third recording state.

20. The data storage device as recited in claim 16 , further comprising a means for writing the data to the disk surface by configuring the magnetic recording layer into one of at least a first recording state, a second recording state, a third recording state, or a fourth recording state.

21. The data storage device as recited in claim 1 , wherein the adjustable detector comprises a slicer comprising adjustable thresholds.

Assignments (5)
PATENT COLLATERAL AGREEMENT - DDTL LOAN AGREEMENT Recorded Aug 21, 2023
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A.
Reel/Frame 067045/0156 →
PATENT COLLATERAL AGREEMENT - A&R LOAN AGREEMENT Recorded Aug 21, 2023
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A.
Reel/Frame 064715/0001 →
RELEASE OF SECURITY INTEREST AT REEL 052025 FRAME 0088 Recorded Feb 8, 2022
From: JPMORGAN CHASE BANK, N.A.
To: WESTERN DIGITAL TECHNOLOGIES, INC.
Reel/Frame 058965/0699 →
SECURITY INTEREST Recorded Feb 26, 2020
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A., AS AGENT
Reel/Frame 052025/0088 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 15, 2020
From: MOHL, AARON K.
To: WESTERN DIGITAL TECHNOLOGIES, INC.
Reel/Frame 051618/0195 →
Cited By (3)
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