M-type hexaferrite having a planar anisotropy

Patent metadata

Field	Value
Publication number	US-12424362-B2
Application number	US-202117923127-A
Country	US
Kind code	B2
Filing date	May 6, 2021
Priority date	May 7, 2020
Publication date	Sep 23, 2025
Grant date	Sep 23, 2025

Abstract

In an aspect, an M-type ferrite comprises an element Me comprising at least one of Ba, Sr, or Pb; an element Me′ comprising at least one of Ti, Zr, Ru, or Ir; and an element Me″ comprising at least one of In or Sc. In another aspect, a method of making the M-type ferrite can comprise milling ferrite precursor compounds comprising oxides of at least Co, Fe, Me, Me′, and Me″ to form an oxide mixture; wherein Me comprises at least one of Ba, Sr, or Pb; Me′ is at least one of Ti, Zr, Ru, or Ir; and Me″ is at least one of In or Sc; and calcining the oxide mixture in an oxygen or air atmosphere to form the ferrite.

First claim

What is claimed is:

1. A ferrite, wherein the ferrite comprises:
an element Me comprising at least one of Ba, Sr, or Pb;
an element Me′ comprising at least one of Ti, Zr, Ru, or Ir; and
an element Me″ comprising at least one of In or Sc; and
wherein the ferrite is an M-type ferrite, and
wherein the ferrite has
an average grain size is of 1 to 100 micrometers, as measured using transmission electron microscopy or field emission scanning electron microscopy,
a permeability of greater than or equal to 37.5 at a frequency of 200 megahertz,
a figure of merit of greater than or equal to 50 at a frequency of 200 megahertz,
a magnetic loss tangent tan δ μ of less than or equal to 0.8 at a frequency of 200 megahertz,
a Snoek product of greater than or equal to 12 gigahertz over the frequency range of 1 to 300 megahertz, or
a combination thereof.

2. The ferrite of claim 1 , wherein the ferrite is in the form of a solid-solution.

3. The ferrite of claim 1 , wherein the ferrite has an average grain size is of 1 to 100 micrometers, as measured using transmission electron microscopy or field emission scanning electron microscopy.

4. The ferrite of claim 1 , wherein the ferrite has a permeability of greater than or equal to 37.5 at a frequency of 200 megahertz.

5. The ferrite of claim 1 , wherein the ferrite has a figure of merit of greater than or equal to 50 at a frequency of 200 megahertz.

6. The ferrite of claim 1 , wherein the ferrite has a magnetic loss tangent tan δ μ of less than or equal to 0.8 at a frequency of 200 megahertz.

7. The ferrite of claim 1 , wherein the ferrite has a Snoek product of greater than or equal to 12 gigahertz over the frequency range of 1 to 300 megahertz.

8. A dual-phase ferrite, wherein the dual-phase ferrite comprises:
a c-plane magnetic structure having a c-plane magnetocrystalline anisotropy and having the formula Me(CoMe′) x Fe 12-2x O 19 , wherein Me is at least one of Ba, Sr, or Pb; Me′ is at least one of Ti, Zr, Ru, or Ir; and x is 0.8 to 1.3; and
a uniaxial magnetic structure having a uniaxial magnetocrystalline anisotropy and having the formula Me(Me″) y Fe 12-y O 19 , wherein Me is defined above; Me″ is at least one of In or Sc; and y is 0.01 to 12.

9. The dual-phase ferrite of claim 8 ,
wherein the dual-phase ferrite has the formula (Me(CoMe′) x Fe 12-2x O 19 ) (MeMe″ y Fe 12-y O 19 ), wherein x is 0.8 to 1.3, y is 0.01 to 12, and z is 0.005 to 2.

10. The dual-phase ferrite of claim 8 , wherein the c-plane magnetic structure has the formula of Ba(CoTi) x Fe 12-2x O 19 , wherein x is 0.8 to 1.3.

11. The dual-phase ferrite of claim 8 , wherein the uniaxial magnetic structure has the formula Ba(In) y Fe 12-y O 19 , wherein y is 0.01 to 6.

12. The dual-phase ferrite of claim 8 , wherein a mole ratio of the c-plane magnetic structure to the uniaxial magnetic structure is 1:0.005 to 1:2.

13. A composite comprising a polymer and the ferrite of claim 1 .

14. A composite comprising:
a polymer comprising at least one of a fluoropolymer or a polyolefin; and
a ferrite comprising
an element Me comprising at least one of Ba, Sr, or Pb;
an element Me′ comprising at least one of Ti, Zr, Ru, or Ir; and
an element Me″ comprising at least one of In or Sc,
wherein the ferrite is an M-type ferrite.

15. An article comprising the ferrite composition of claim 1 .

16. The article of claim 15 , wherein the article is an antenna, a filter, an inductor, a circulator, or an EMI suppressor.

17. A method of making the dual-phase ferrite of claim 8 , the method comprising:
milling ferrite precursor compounds comprising oxides of at least Co, Fe, Me, Me′, and Me″ to form an oxide mixture; and
calcining the oxide mixture in an oxygen or air atmosphere to form the dual-phase ferrite.

18. The method of claim 17 , wherein the milling the ferrite precursor compounds comprises:
milling the ferrite precursor compounds comprising oxides of at least Co, Fe, Me, and Me′ to form a first oxide mixture; and
milling the ferrite precursor compounds comprising oxides of at least Fe, Me, and Me″ to form a second oxide mixture;
wherein the calcining comprises separately calcining the first oxide mixture and the second oxide mixture or calcining a mixture comprising the first oxide mixture and the second oxide mixture.

19. The method of claim 18 , wherein the calcining comprises separately calcining the first oxide mixture and the second oxide mixture to form separately calcined mixtures; and the method further comprises mixing the separately calcined mixture to form the dual-phase ferrite.

20. The method of claim 17 , further comprising post-annealing the ferrite in an oxygen or air atmosphere after the milling.

21. The method of claim 17 , wherein the calcining the calcined ferrite occurs at a calcining temperature of 800 to 1,300° C. for a calcining time of 0.5 to 20 hours.

22. A method of forming a composite, comprising:
forming a dual-phase ferrite according to the process of claim 17 ; and
mixing the dual-phase ferrite and a polymer.

Assignees

• Rogers Corp

Inventors

• Chen Yajie
• Wang Yu

Classifications

• C04B2235/767

  Hexagonal symmetry, e.g. beta-Si3N4, beta-Sialon, alpha-SiC or hexa-ferrites · CPC title

• C04B2235/786

  Micrometer sized grains, i.e. from 1 to 100 micron · CPC title

• C04B2235/3275

  Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite · CPC title

• C04B2235/3296

  Lead oxides, plumbates or oxide forming salts thereof, e.g. silver plumbate · CPC title

• C04B2235/3286

  Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate · CPC title