Effective substitutions for rare earth metals in compositions and materials for electronic applications

Patent metadata

Field	Value
Publication number	US-9527776-B2
Application number	US-201414191096-A
Country	US
Kind code	B2
Filing date	Feb 26, 2014
Priority date	Nov 30, 2010
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

Embodiments disclosed herein include methods of modifying synthetic garnets used in RF applications to reduce or eliminate Yttrium or other rare earth metals in the garnets without adversely affecting the magnetic properties of the material. Some embodiments include substituting Bismuth for some of the Yttrium on the dodecahedral sites and introducing one or more high valency ions to the octahedral and tetrahedral sites. Calcium may also be added to the dodecahedral sites for valency compensation induced by the high valency ions, which could effectively displace all or most of the Yttrium (Y) in microwave device garnets. The modified synthetic garnets with substituted Yttrium (Y) can be used in various microwave magnetic devices such as circulators, isolators and resonators.

First claim

What is claimed is:

1. A modified yttrium iron garnet comprising:
Bi x Ca y+2z Y 3−x−y−2z Fe 5−y−z Zr y V z O 12 , x being greater than or equal to 0.5 and less than or equal to 1.4, y being greater than or equal to 0.3 and less than or equal to 0.55, and z being greater than or equal to 0 and less than or equal to 0.6, the modified yttrium iron garnet having a magnetic resonance linewidth of less than or equal to 11 Oersted.

2. A microwave device incorporating the modified yttrium iron garnet of claim 1 .

3. The microwave device of claim 2 wherein said microwave device is selected from the group consisting of isolators, circulators, and resonators.

4. A method of forming a modified yttrium iron garnet comprising:
providing a material including oxides, carbonates, or a combination thereof;
blending the material to form a mixture;
drying the mixture at a temperature between 100-400° C.;
sieving the dried mixture;
calcining the sieved mixture at a temperature between 800-1000° C.;
milling the calcined material into particles sizes of about 0.5 micron to 10 microns;
spray drying the milled material to form granules;
pressing the granules; and
calcining the pressed granules at a temperature between about 850-1000° C. to form a composition represented by the formula:
Bi x Ca y+2z Y 3−x−y−2z Fe 5−y−z Zr y V z O 12 , x being greater than or equal to 0.5 and less than or equal to 1.4, y being greater than or equal to 0.3 and less than or equal to 0.55, and z being greater than or equal to 0 and less than or equal to 0.6.

5. The method of claim 4 wherein calcining the sieved mixture is at a temperature between about 900-950° C.

6. The method of claim 4 wherein milling is performed in a vibratory mill, an attrition mill, or a jet mill.

7. The method of claim 4 wherein the pressed material has a density of around 60% prior to calcining the milled material.

8. A microwave device incorporating a modified yttrium iron garnet, the microwave device comprising:
Bi 1.4 Ca 0.55+2x Y 1.05−2x Zr 0.55 V x Fe 4.45−x O 12 , x being greater than or equal to 0 and less than or equal to 0.525, Bi and Ca occupying the dodecahedral sites, Zr occupying the octahedral sites, and V occupying the tetrahedral sites of the garnet.

9. The microwave device of claim 8 wherein said microwave device is selected from the group consisting of isolators, circulators, and resonators.

10. A microwave device formed from a modified yttrium iron garnet, the microwave device comprising:
Bi x Ca y+2z Y 3−x−y−2z Fe 5−y−z Zr y V z O 12 , x being greater than or equal to 0.5 and less than or equal to 1.4, y being greater than or equal to 0.3 and less than or equal to 0.55, and z being greater than or equal to 0 and less than or equal to 0.6.

11. The microwave device of claim 10 wherein said microwave device is selected from the group consisting of isolators, circulators, and resonators.

Assignees

• Skyworks Solutions Inc

Inventors

• Cruickshank David Bowie
• Hill Michael David

Classifications

• C04B2235/3248

  Zirconates or hafnates, e.g. zircon · CPC title

• C04B2235/656

  characterised by specific heating conditions during heat treatment · CPC title

• H01F10/245

  Modifications for enhancing interaction with electromagnetic wave energy · CPC title

• C04B2235/96

  Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance · CPC title

• C04B2235/764

  Garnet structure A3B2(CO4)3 · CPC title