US 12,272,475 B2
Magnetically anisotropic binder-free films containing discrete hexaferrite nanoplatelets
Shanying Cui, Calabasas, CA (US); Xin N. Guan, Monterey Park, CA (US); Adam F. Gross, Santa Monica, CA (US); and Florian G. Herrault, Agoura Hills, CA (US)
Assigned to HRL Laboratories, LLC, Malibu, CA (US)
Filed by HRL Laboratories, LLC, Malibu, CA (US)
Filed on Feb. 28, 2022, as Appl. No. 17/682,478.
Application 17/682,478 is a division of application No. 16/592,477, filed on Oct. 3, 2019, granted, now 11,295,882.
Claims priority of provisional application 62/804,291, filed on Feb. 12, 2019.
Prior Publication US 2022/0351885 A1, Nov. 3, 2022
Int. Cl. H01F 1/34 (2006.01); H01F 10/20 (2006.01); H01F 10/28 (2006.01); H01F 10/30 (2006.01); H01F 41/24 (2006.01); H01P 1/36 (2006.01); H01P 1/38 (2006.01)
CPC H01F 1/348 (2013.01) [H01F 10/205 (2013.01); H01F 10/28 (2013.01); H01F 10/30 (2013.01); H01F 41/24 (2013.01); H01P 1/36 (2013.01); H01P 1/38 (2013.01)] 39 Claims
OG exemplary drawing
 
1. A method of making a magnetically anisotropic structure, said method comprising:
(a) synthesizing or obtaining magnetic hexaferrite particles;
(b) if said magnetic hexaferrite particles are agglomerated, mechanically treating said magnetic hexaferrite particles to form discrete particles;
(c) combining said magnetic hexaferrite particles with a solvent, to generate a dispersion;
(d) depositing said magnetic hexaferrite particles onto a substrate via drying and/or charge-titration assembly, to generate a magnetically anisotropic film of aligned, discrete magnetic hexaferrite particles disposed on said substrate;
(e) optionally embedding said magnetically anisotropic film in a polymer; and
(f) recovering a magnetically anisotropic structure containing said magnetically anisotropic film, said substrate, and, if present, said polymer,
wherein the maximum processing temperature during said method is 500° C. or less, and
wherein said discrete magnetic hexaferrite particles are aligned with a full width at half maximum angular distribution of the hexaferrite particle c-axis direction of about ±20° or less.