Modified ni-zn ferrites for radiofrequency applications

Patent metadata

Field	Value
Publication number	US-2020127367-A1
Application number	US-201916655723-A
Country	US
Kind code	A1
Filing date	Oct 17, 2019
Priority date	Sep 22, 2010
Publication date	Apr 23, 2020
Grant date	—

Abstract

Embodiments disclosed herein relate to using cobalt (Co) to fine tune the magnetic properties, such as permeability and magnetic loss, of nickel-zinc ferrites to improve the material performance in electronic applications. The method comprises replacing nickel (Ni) with sufficient Co+2 such that the relaxation peak associated with the Co+2 substitution and the relaxation peak associated with the nickel to zinc (Ni/Zn) ratio are into near coincidence. When the relaxation peaks overlap, the material permeability can be substantially maximized and magnetic loss substantially minimized. The resulting materials are useful and provide superior performance particularly for devices operating at the 13.56 MHz ISM band.

First claim

1 . (canceled)

2 . A fine-tuned nickel-zinc ferrite material comprising:
a base nickel-zinc ferrite material doped with cobalt (CO 2+ ) to adjust a nickel to zinc ratio of the base nickel-zinc ferrite material thereby providing a Ni/Zn relaxation absorption peak at a desired frequency above a desired low magnetic loss frequency, the cobalt being doped into the base nickel-zinc ferrite material to a level where a cobalt dominated relaxation peak merges into a low frequency end of the Ni/Zn relaxation absorption peak, the fine-tuned nickel-zinc ferrite material being represented by the formula Ni 1-x-y Zn x Co y Fe 2 O 4 , x being between 0.2 and 0.6, and y being between 0 and 0.2

3 . The fine-tuned nickel-zinc ferrite material of claim 2 wherein the fine-tuned nickel-zinc ferrite material has a composition Ni 0.5725 Co 0.0275 Zn 0.4 Fe 2 O 4 .

4 . The fine-tuned nickel-zinc ferrite material of claim 2 wherein the base nickel-zinc ferrite material has a composition Ni 0.5 Zn 0.5 Fe 2 O 4 .

5 . The fine-tuned nickel-zinc ferrite material of claim 2 wherein the fine-tuned nickel-zinc ferrite material has a permeability in excess of 100.

6 . The fine-tuned nickel-zinc ferrite material of claim 2 wherein the desired frequency is about 100 MHz.

7 . A radiofrequency component comprising:
a base nickel-zinc ferrite material doped with cobalt (CO 2+ ) to adjust a nickel to zinc ratio of the base nickel-zinc ferrite material thereby providing a Ni/Zn relaxation absorption peak at a desired frequency above a desired low magnetic loss frequency, the cobalt being doped into the base nickel-zinc ferrite material to a level where a cobalt dominated relaxation peak merges into a low frequency end of the Ni/Zn relaxation absorption peak, the fine-tuned nickel-zinc ferrite material being represented by the formula Ni 1-x-y Zn x Co y Fe 2 O 4 , x being between 0.2 and 0.6, and y being between 0 and 0.2

8 . The radiofrequency component of claim 7 wherein the fine-tuned nickel-zinc ferrite material has a composition Ni 0.5725 Co 0.0275 Zn 0.4 Fe 2 O 4 .

9 . The radiofrequency component of claim 7 wherein the base nickel-zinc ferrite material has a composition Ni 0.5 Zn 0.5 Fe 2 O 4 .

10 . The radiofrequency component of claim 7 wherein the fine-tuned nickel-zinc ferrite material has a permeability in excess of 100.

11 . The radiofrequency component of claim 7 wherein the desired frequency is about 100 MHz.

12 . The radiofrequency component of claim 7 wherein the component is included in an antenna.

13 . The radiofrequency component of claim 12 wherein the antenna is configured to facilitate transmission and reception of radiofrequency signals in the 13.56 MHz range.

14 . The radiofrequency component of claim 7 wherein the component is included in a battery.

15 . The radiofrequency component of claim 7 wherein the component is included in a glucose sensor.

16 . A method of fine tuning nickel-zinc ferrite material into a fine-tuned nickel-zinc ferrite material, said method comprising:
adjusting a nickel to zinc ratio of a base nickel-ferrite material to provide a Ni/Zn relaxation absorption peak at a desired frequency above a desired low magnetic loss frequency; and doping the material with cobalt (CO 2+ ) to a level where a cobalt dominated relaxation peak merges into a low frequency end of the Ni/Zn relaxation absorption peak, the material being represented by the formula Ni 1-x-y Zn x Co y Fe 2 O 4 , x being between 0.2 and 0.6, and y being between 0 and 0.2.

17 . The method of claim 16 wherein the fine-tuned nickel-zinc ferrite material has a composition Ni 0.5725 Co 0.0275 Zn 0.4 Fe 2 O 4 .

18 . The method of claim 16 wherein the base nickel-zinc ferrite material has a composition Ni 0.5 Zn 0.5 Fe 2 O 4 .

19 . The method of claim 16 wherein the fine-tuned nickel-zinc ferrite material has a permeability in excess of 100.

20 . The method of claim 16 wherein the desired frequency is about 100 MHz.

21 . The method of claim 16 further comprising calcining the fine-tuned nickel-zinc ferrite material at a temperature range of 1100° C.-1400° C.

Assignees

• Skyworks Solutions Inc

Inventors

• Hill Michael David
• Cruickshank David Bowie
• Anderson Kelvin Mitchell

Classifications

• C04B2235/81

  Materials characterised by the absence of phases other than the main phase, i.e. single phase materials · CPC title

• C01G49/0018

  Mixed oxides or hydroxides, (C01G49/0009 takes precedence) · CPC title

• C01P2002/32

  spinel-type (AB2O4) · CPC title

• C01P2006/40

  Electric properties · CPC title

• C04B2235/3275

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