All-optical magnetic recording system using FeMnPt media

Patent metadata

Field	Value
Publication number	US-9280996-B2
Application number	US-201314106587-A
Country	US
Kind code	B2
Filing date	Dec 13, 2013
Priority date	Dec 13, 2013
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

Abstract

An “all optical switching” (AOS) magnetic recording system, i.e., one that does not require a magnetic field to reverse the magnetization in the magnetic recording media, uses a FeMnPt L1 0 alloy as the magnetic media. A FeMnPt alloy, with appropriate amounts of Mn, will have high magneto-crystalline anisotropy, but also ferrimagnetic spin alignment for triggering AOS. The combination of high magneto-crystalline anisotropy and ferrimagnetic spin configuration enables the FeMnPt media to function as magnetic media whose magnetization can be switched solely by polarized laser pulses. The FeMnPt media for may be a single layer with or without any segregants. Alternatively, the FeMnPt media may be a multilayered recording layer comprising alternating layers of FePt and MnPt L1 0 ordered alloys. The segregant-free embodiments of the FeMnPt material may be patterned to form bit-patterned-media (BPM).

First claim

What is claimed is:

1. An all-optical magnetic recording system comprising:
a magnetic recording medium comprising a generally planar substrate and a continuous non-bit-patterned magnetic recording layer on the substrate, the recording layer comprising a FeMnPt alloy wherein Mn is present in said alloy in an amount greater than or equal to 1 atomic percent and less than or equal to 15 atomic percent;
a laser for generating light;
a polarizer for polarizing the laser light;
means for directing the polarized laser light to the recording layer to switch the magnetization of regions of the recording layer; and

wherein the system does not include a write head for generating a magnetic field.

2. The system of claim 1 wherein the recording layer has a composition of the form (Fe (100-x) Mn x ) y Pt (100-y) , where the subscripts represent atomic percent, y is greater than or equal to 45 and less than or equal to 55 and x is greater than or equal to 2 and less than or equal to 30.

3. The system of claim 1 wherein the recording layer is a single layer having a thickness greater than or equal to 5 nm and less than or equal to 15 nm.

4. The system of claim 1 wherein the recording layer further comprises one or more segregants selected from C, B, BN, SiN, CrN, SiOx, TiOx, TaOx and CrOx.

5. The system of claim 1 wherein the recording layer is a multilayer comprising alternating layers of at least one layer comprising a FePt alloy and at least one layer comprising a MnPt alloy.

6. The system of claim 5 wherein the at least one layer comprising a FePt alloy further comprises one or more segregants selected from C, B, BN, SiN, CrN, SiOx, TiOx, TaOx and CrOx.

7. The system of claim 5 wherein the at least one layer comprising a FePt alloy further comprises one or more segregants selected from C, B, BN, SiN, CrN, SiOx, TiOx, TaOx and CrOx and the least one layer comprising a MnPt further comprises one or more segregants selected from C, B, BN, SiN, CrN, SiOx, TiOx, TaOx and CrOx.

8. The system of claim 5 wherein the ratio of the thickness of said at least one layer comprising a FePt alloy to the thickness of said at least one layer comprising a MnPt alloy is selected such that the amount of Mn present in the multilayer is greater than or equal to 1 atomic percent and less than or equal to 15 atomic percent of the total amount of Fe, Pt and Mn in the multilayer.

9. The system of claim 1 wherein the polarizer is a circular polarizer.

10. The system of claim 1 wherein the means for directing the polarized laser light comprises an optical channel.

11. The system of claim 1 wherein the means for directing the polarized laser light comprises a near-field transducer.

12. An all-optical magnetic recording system comprising:
a magnetic recording medium comprising a generally planar substrate and a continuous non-bit-patterned recording layer on the substrate and having a composition of the form (Fe (100-x) Mn x ) y Pt (100-y) , where the subscripts represent atomic percent, y is greater than or equal to 45 and less than or equal to 55 and x is greater than or equal to 2 and less than or equal to 30;
a laser for generating light;
a polarizer for circularly polarizing the laser light; and
a transducer for directing the circularly polarized light to the recording layer to switch magnetized regions of the recording layer without the assistance of a magnetic field.

13. The system of claim 12 wherein the recording layer further comprises one or more segregants selected from C, B, BN, SiN, CrN, SiOx, TiOx, TaOx and CrOx.

14. The system of claim 12 wherein the recording layer is a multilayer comprising alternating layers of at least one layer comprising a FePt alloy and at least one layer comprising a MnPt alloy.

15. The system of claim 14 wherein the at least one layer comprising a FePt alloy further comprises one or more segregants selected from C, B, BN, SiN, CrN, SiOx, TiOx, TaOx and CrOx and the least one layer comprising a MnPt further comprises one or more segregants selected from C, B, BN, SiN, CrN, SiOx, TiOx, TaOx and CrOx.

16. The system of claim 12 further comprising an optical channel for directing the circularly polarized light to the transducer.

17. The system of claim 16 wherein the optical channel comprises a waveguide having a substantially planar surface facing the substrate of the magnetic recording medium, and wherein the transducer is formed on said substantially planar waveguide surface.

18. The system of claim 12 wherein the medium is a rotatable disk and the recording layer has a plurality of data tracks, and further comprising a carrier connected to the transducer and an actuator connected to the carrier for moving the carrier to selected data tracks.

Assignees

• HGST Netherlands BV

Inventors

• Hellwig Olav
• Mosendz Oleksandr
• Weller Dieter K

Classifications

• G11B5/66

  the record carriers consisting of several layers · CPC title

• G11B5/65

  characterised by its composition (G11B5/66 takes precedence) · CPC title

• G11B5/653 Primary

  containing Fe or Ni (containing Co G11B5/656; containing inorganic, non-oxide compounds of Si, N, P, B, H or C G11B5/657; containing oxygen G11B5/658) · CPC title

• G11B7/242

  of recording layers · CPC title

• G11B11/10 Primary

  using recording by magnetic means {or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field} · CPC title