Magnetic material including α″-Fe16(NxZ1-x)2 or a mixture of α″-Fe16Z2 and α″-Fe16N2, where Z includes at least one of C, B, or O

Patent metadata

Field	Value
Publication number	US-10072356-B2
Application number	US-201514820284-A
Country	US
Kind code	B2
Filing date	Aug 6, 2015
Priority date	Aug 8, 2014
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

A magnetic material may include α″-Fe 16 (N x Z 1-x ) 2 or a mixture of α″-Fe 16 N 2 and α″-Fe 16 Z 2 , where Z includes at least one of C, B, or O, and x is a number greater than zero and less than one. In some examples, the magnetic material including α″-Fe 16 (N x Z 1-x ) 2 or a mixture of α″-Fe 16 N 2 and α″-Fe 16 Z 2 may include a relatively high magnetic saturation, such as greater than about 219 emu/gram, greater than about 242 emu/gram, or greater than about 250 emu/gram. In addition, in some examples, the magnetic material including α″-Fe 16 (N x Z 1-x ) 2 or a mixture of α″-Fe 16 N 2 and α″-Fe 16 Z 2 may include a relatively low coercivity. Techniques for forming the magnetic material are also described.

First claim

What is claimed is:

1. A soft magnetic material comprising:
at least one of an α″-Fe 16 (N x Z 1-x ) 2 phase domain or an α′-Fe 8 (N x Z 1-x ) phase domain, wherein Z includes at least one of C, B, or O, and wherein x is a number greater than zero and less than one, wherein the at least one of the α″-Fe 16 (N x Z 1-x ) 2 phase domain or the α′-Fe 8 (N x Z 1-x ) phase domain comprises a plurality of at least one of α″-Fe 16 (N x Z 1-x ) 2 crystals or α′-Fe 8 (N x Z 1-x ) crystals, and wherein respective [001] axes of the plurality of crystals are randomly distributed within the soft magnetic material.

2. The soft magnetic material of claim 1 , wherein x is equal to about 0.5.

3. The soft magnetic material of claim 1 , wherein x is equal to about 0.4667.

4. The soft magnetic material of claim 1 , wherein Z consists of C.

5. The soft magnetic material of claim 1 , further comprising at least one of an α″-Fe 16 N 2 phase domain, an α″-Fe 16 Z 2 phase domain, a α′-Fe 8 (N) phase domain, or an α′-Fe 8 (Z) phase domain.

6. The soft magnetic material of claim 1 , comprising a saturation magnetization of at least about 219 emu/gram.

7. The soft magnetic material of claim 1 , comprising a magnetic coercivity of less than or equal to about 10 Oersteds.

8. The soft magnetic material of claim 1 , wherein at least about 35 volume percent of the soft magnetic material is the at least one of the α″-Fe 16 (N x Z 1-x ) 2 phase domain or the α′-Fe 8 (N x Z 1-x ) phase domain.

9. The soft magnetic material of claim 1 , wherein at least about 60 volume percent of the soft magnetic material is the at least one of the α″-Fe 16 (N x Z 1-x ) 2 phase domain or the α′-Fe 8 (N x Z 1-x ) phase domain.

10. A soft magnetic material comprising:
at least one of an α″-Fe 16 N 2 phase domain or an α′-Fe 8 N phase domain; and
at least one of an α″-Fe 16 Z 2 phase domain or an α′-Fe 8 Z phase domain, wherein Z includes at least one of C, B, or O, wherein the at least one of the α″-Fe 16 N 2 phase domain or the α′-Fe 8 N phase domain comprises a plurality of at least one of α″-Fe 16 N 2 crystals or α′-Fe 8 N crystals, wherein the at least one α″-Fe 16 Z 2 phase domain comprises a plurality of at least one of α″-Fe 16 Z 2 crystals or α′-Fe 8 Z crystals and wherein respective [001] axes of the plurality of at least one of α″-Fe 16 N 2 crystals or α′-Fe 8 N crystals and respective [001] axes of the plurality of at least one of α″-Fe 16 Z 2 crystals or α′-Fe 8 Z crystals are randomly distributed within the soft magnetic material.

11. The soft magnetic material of claim 10 , wherein the at least one of the α″-Fe 16 N 2 phase domain or the α′-Fe 8 N phase domain comprises a first layer comprising the at least one of the α″-Fe 16 N 2 phase domain or the α′-Fe 8 N phase domain, wherein the α″-Fe 16 Z 2 phase domain comprises a second layer comprising the at least one of the α″-Fe 16 Z 2 phase domain or the α′-Fe 8 Z phase domain, and wherein the first layer and the second layer are adjacent to each other.

12. The soft magnetic material of claim 10 , wherein the at least one of the α″-Fe 16 N 2 phase domain or the α′-Fe 8 N phase domain comprises a first set of layers, each layer of the first set of layers comprising the at least one of the α″-Fe 16 N 2 phase domain or the α′-Fe 8 N phase domain, wherein the at least one of the α″-Fe 16 Z 2 phase domain or the α′-Fe 8 Z phase domain comprises a second set of layers, each layer of the second set of layers comprising the at least one of the α″-Fe 16 Z 2 phase domain or the α′-Fe 8 Z phase domain, and wherein one or more respective layers of the first set of layers alternate with one or more respective layers of the second set of layers.

13. The soft magnetic material of claim 10 , wherein Z consists of C.

14. The soft magnetic material of claim 10 , comprising a saturation magnetization of at least about 219 emu/gram.

15. The soft magnetic material of claim 10 , comprising a magnetic coercivity of less than or equal to about 10 Oersteds.

16. The soft magnetic material of claim 10 , wherein the at least one of the α″-Fe 16 N 2 phase domain or the α′-Fe 8 N phase domains and the at least one of the α″-Fe 16 Z 2 phase domain or the α′-Fe 8 Z phase domain together form at least about 35 volume percent of the soft magnetic material.

17. The soft magnetic material of claim 10 , wherein the at least one of the α″-Fe 16 N 2 phase domain or the α′-Fe 8 N phase domain and the at least one of the α″-Fe 16 Z 2 phase domain or the α′-Fe 8 Z phase domain together form at least about 60 volume percent of the soft magnetic material.

18. A method comprising:
forming a soft magnetic material comprising at least one of:
at least one of an α″-Fe 16 (N x Z 1-x ) 2 phase domain or an α′-Fe 8 (N x Z 1-x ), wherein Z includes at least one of C, B, or O, wherein x is a number greater than zero and less than one, wherein the at least one of the α″-Fe 16 (N x Z 1-x ) 2 phase domain or the α′-Fe 8 (N x Z 1-x ) phase domain comprises a plurality of at least one of α″-Fe 16 (N x Z 1-x ) 2 crystals or α′-Fe 8 (N x Z 1-x ) crystals, and wherein respective [001] axes of the plurality of crystals are randomly distributed within the soft magnetic material; or
at least one of an α″-Fe 16 N 2 phase domain or an α′-Fe 8 N phase domain, and at least one of an α″-Fe 16 Z 2 phase domain or an α′-Fe 8 Z phase domain, wherein the at least one of the α″-Fe 16 N 2 phase domain or the α′-Fe 8 N phase domain comprises a plurality of at least one of α″-Fe 16 N 2 crystals or α′-Fe 8 N crystals, wherein the at least one α″-Fe 16 Z 2 phase domain comprises a plurality of at least one of α″-Fe 16 Z 2 crystals or α′-Fe 8 Z crystals and wherein respective [001] axes of the plurality of at least one of α″-Fe 16 N 2 crystals or α′-Fe 8 N crystals and respective [001] axes of the plurality of at least one of α″-Fe 16 Z 2 crystals or α′-Fe 8 Z crystals are randomly distributed within the soft magnetic material.

19. The method of claim 18 , wherein forming the soft magnetic material comprises sputtering from a carbon-doped iron target to form a layer comprising iron, carbon, and nitrogen over a substrate.

20. The method of claim 19 , wherein the carbon-doped iron target comprises between about 1 at. % and about 10 at. % carbon.

21. The method of claim 19 , wherein sputtering comprises forming a nitrogen plasma to provide a source of nitrogen atoms.

22. The method of claim 19 , further comprising annealing the layer at a temperature between about 100° C. and about 210° C. for between about 5 hours and about 100 hours.

23. The method of claim 18 , wherein forming the soft magnetic material comprises depositing the soft magnetic material over a substrate using at least one of chemical vapor deposition, molecular beam epitaxy, low temperature epitaxy, liquid phase epitaxy, or ion implantation.

24. The method of claim 18 , wherein forming the soft magnetic material comprises:
straining an iron workpiece comprising at least one iron crystal in a direction substantially parallel to a <001> crystal axis of the iron crystal;
nitridizing and carbonizing the iron workpiece to form a nitridized and carbonized iron wire or sheet; and
annealing the nitridized and carbonized iron workpiece to form the soft magnetic material.

25. The method of claim 18 , wherein forming the soft magnetic material comprises:
implanting nitrogen and carbon atoms in an iro

Assignees

• Univ Minnesota

Inventors

• Wang Jian-Ping
• Jiang Yanfeng
• Mehedi Md Aminul

Classifications

• C23C14/5806

  Thermal treatment · CPC title

• C30B23/00

  Single-crystal growth by condensing evaporated or sublimed materials · CPC title

• C21D1/26

  Methods of annealing · CPC title

• C30B29/38 Primary

  Nitrides · CPC title

• H01F41/18

  by cathode sputtering · CPC title