All-nanoparticle concave diffraction grating fabricated by self-assembly onto magnetically-recorded templates

Patent metadata

Field	Value
Publication number	US-10381035-B2
Application number	US-201414251889-A
Country	US
Kind code	B2
Filing date	Apr 14, 2014
Priority date	Apr 12, 2013
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

Methods for magnetic recording are provided. The method can include: assembling a plurality of nanoparticles into a pattern on a disc; applying a polymer composition onto the pattern of nanoparticles; curing the polymer composition to form a polymer film on the disc, wherein the plurality of nanoparticles are immobilized in the pattern within the polymer film upon curing; and removing the polymer film containing the plurality of nanoparticles in the pattern. Diffraction gratings are also provided that can include a polymeric film comprising a plurality of nanoparticles immobilized in a pattern, wherein the polymer film defines a curvature.

First claim

What is claimed:

1. A method for magnetic recording, comprising:
depositing a solution onto a surface of a magnetic disc medium, the magnetic disc medium comprising magnetic field gradients near the surface, the solution comprising a plurality of magnetic nanoparticles, the magnetic nanoparticles self-assembling upon the deposition into a pattern on the disc, the magnetic field gradients near the surface of the magnetic disc medium determining the pattern of the magnetic nanoparticles;
applying a uniform external magnetic field to the magnetic disc medium during nanoparticle self-assembly;
applying a polymer composition onto the magnetic nanoparticles;
curing the polymer composition to form a polymer film on the disc, wherein the plurality of magnetic nanoparticles are immobilized in the pattern within the polymer film upon curing to form a diffraction grating; and
removing the polymer film containing the plurality of magnetic nanoparticles in the pattern, wherein the polymer film defines a curvature, wherein the diffraction grating is concave.

2. The method as in claim 1 , wherein the magnetic nanoparticles comprise Fe 3 O 4 nanoparticles or cobalt ferrite nanoparticles.

3. The method as in claim 1 , wherein the polymer is applied via a spin-coating process with a liquid polymer composition.

4. The method as in claim 1 , wherein the polymer film is removed via a peeling process using an adhesive tape.

5. The method as in claim 1 , further comprising washing the magnetic nanoparticles with a phosphate buffer solution following the self-assembly of the magnetic nanoparticles on the surface.

6. The method as in claim 1 , wherein the polymer film as a thickness that is greater than 200 nm.

7. The method as in claim 1 , wherein the polymer film is transparent.

8. The method of claim 1 , further comprising:
after curing the polymer composition to form the polymer film but before removing the polymer film from the disc,
assembling a second plurality of nanoparticles into a second pattern over the cured polymer film on the disc;
applying a second polymer composition onto the second pattern of nanoparticles; and
curing the second polymer composition to form a second polymer film on the underlying polymer film on the disc, wherein the second plurality of nanoparticles are immobilized in the second pattern within the second polymer film upon curing.

9. The method of claim 8 , further comprising:
after curing the second polymer composition to form the second polymer film but before removing the polymer film from the disc,
assembling a third plurality of nanoparticles into a third pattern over the cured second polymer film on the disc;
applying a third polymer composition onto the third pattern of nanoparticles; and
curing the third polymer composition to form a third polymer film on the underlying second polymer film, wherein the third plurality of nanoparticles are immobilized in the third pattern within the third polymer film upon curing.

10. The method as in claim 1 , wherein the nanoparticles comprise cobalt ferrite nanoparticles having an average diameter of 10 nm to 20 nm.

11. The method as in claim 1 , wherein the polymer film is removed via a peeling process using an adhesive tape defining a hole therein.

12. The method as in claim 11 , wherein, upon peeling, the polymer film containing the plurality of nanoparticles in the pattern is suspended within the hole.

13. The method as in claim 1 , wherein the magnetic nanoparticles comprise superparamagnetic particles.

14. The method as in claim 1 , the magnetic disc medium comprising a magnetization of about 450 kA/m.

15. The method as in claim 1 , further comprising prior to depositing the solution onto the surface of the magnetic disc medium, magnetically recording a transition pattern into the magnetic disc medium.

16. The method as in claim 1 , the magnetic nanoparticles comprising an electrostatically charged ligand on a surface of the nanoparticles.

Assignees

• Univ South Carolina

Inventors

• Crawford Thomas M
• Ye Longfei
• Henderson Jason Ryan

Classifications

• G11B5/59688

  Servo signal format patterns or signal processing thereof, e.g. dual, tri, quad, burst signal patterns · CPC title

• G11B5/746

  Bit Patterned record carriers, wherein each magnetic isolated data island corresponds to a bit · CPC title

• H01F1/11

  in the form of particles {(for magnetic record carriers G11B5/70626)} · CPC title

• G02B5/1847

  Manufacturing methods · CPC title

• G11B5/855 Primary

  Coating only part of a support with a magnetic layer · CPC title