Composite hexagonal ferrite materials
Disclosed herein are embodiments of composite hexagonal ferrite materials formed from a combination of Y phase and Z phase hexagonal ferrite materials. Advantageously, embodiments of the material can have a high resonant frequency as well as a high permeability. In some embodiments, the materials can be useful for magnetodielectric antennas.
1. A composite hexagonal ferrite material, the material comprising:
a base y-phase hexagonal ferrite composition having a formula Sr 2-x Na x Co 2-x Sc x Fe 12 O 22 , 0<x<1; and
a doped-in z-phase hexagonal ferrite composition to form the composite hexagonal ferrite material, the composite hexagonal ferrite m-phase hexagonal ferrite composition material having a Q value of greater than about 15 at 1 GHz.
2. The composite hexagonal ferrite material of claim 1 wherein the material has a Q value of greater than about 20 at 1 GHz.
3. The composite hexagonal ferrite material of claim 1 wherein the material has a real permeability of between 3 and 7 at 1 GHz.
4. The composite hexagonal ferrite material of claim 1 wherein the material has a real permeability of greater than 6.
5. The composite hexagonal ferrite material of claim 1 wherein the z-phase hexagonal ferrite composition comprises Ba 1.4 Sr 0.8 Na 0.8 Co 1.2 Sc 0.8 Fe 24 O 41 .
6. The composite hexagonal ferrite material of claim 1 wherein the y-phase hexagonal ferrite composition comprises Sr 1.6 Na 0.4 Sc 0.4 Co 1.6 Fe 12 O 22 .
7. The composite hexagonal ferrite material of claim 1 further including Ba 3 Co 2 Fe 24 O 41 , Sr 3 Co 2 Fe 24 O 41 , MnO 2 , Al 2 O 3 , or SiO 2 .
8. A method of forming a composite hexagonal ferrite material the method comprising combing a y-phase hexagonal ferrite composition having a formula Sr 2-x Na x Co 2-x Sc x Fe 12 O 22 , 0<x<1, at least partially with a z-phase hexagonal ferrite composition, thereby forming a composite hexagonal ferrite material having a Q value of greater than about 15 at 1 GHz.
9. The method of claim 8 , further including doping the material with indium or zirconium to reduce strontium levels.
10. The method of claim 8 wherein the composite hexagonal ferrite material has a Q value of greater than about 20 at 1 GHz.
11. The method of claim 8 wherein the composite hexagonal ferrite material has a real permeability of between 3 and 7 at 1 GHz.
12. The method of claim 8 wherein the z-phase hexagonal ferrite composition comprises Ba 1.4 Sr 0.8 Na 0.8 Co 1.2 Sc 0.8 Fe 24 O 41 .
13. The method of claim 8 wherein the y-phase hexagonal ferrite composition comprises Sr 1.6 Na 0.4 Sc 0.4 Co 1.6 Fe 12 O 22 .
14. An antenna formed from a composite hexagonal ferrite material, the antenna comprising:
a base y-phase hexagonal ferrite composition having a formula Sr 2-x Na x Co 2-x Sc x Fe 12 O 22 , 0<x<1; and
a doped-in z-phase hexagonal ferrite composition to form the composite hexagonal ferrite material, the composite hexagonal ferrite material having a Q value of greater than about 15 at 1 GHz.
15. The antenna of claim 14 wherein the antenna is part of a wireless device.
16. The antenna of claim 15 wherein the antenna is part of a tablet.
17. The antenna of claim 14 wherein the antenna is usable at frequencies of 1 GHz and above.
18. The antenna of claim 14 wherein the composite hexagonal ferrite material has a Q value of greater than about 20 at 1 GHz and a real permeability of between 3 and 7 at 1 GHz.
19. The antenna of claim 14 wherein the z-phase hexagonal ferrite composition comprises Ba 1.4 Sr 0.8 Na 0.8 Co 1.2 Sc 0.8 Fe 24 O 41 .
20. The antenna of claim 14 wherein the y-phase hexagonal ferrite composition comprises Sr 1.6 Na 0.4 Sc 0.4 Co 1.6 Fe 12 O 22 .