Increased damping of magnetization in magnetic materials

• US 6,452,240 B1
• Filed: 10/30/2000
• Issued: 09/17/2002
• Est. Priority Date: 10/30/2000
• Status: Expired due to Term

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Koch, Roger H., Parkin, Stuart S., Ingvarsson, Snorri T., Xiao, Gang
• Primary Examiner(s): Elms, Richard
• Assistant Examiner(s): MENZ, DOUGLAS M
• Application Number:
  US09/699,651
• Time in Patent Office: 687 Days
• Field of Search: 257/421, 257/422, 257/295, 257/426, 257/427, 365/173, 365/171, 365/158, 428/693
• US Class Current: 257/421
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G11C 11/15 using multiple magnetic layers G11C11/155 takes precedence
• CPC Class Codes: H01F 1/147 Alloys characterised by their composition treatment thereof for enhancing their electromagnetic properties C21D8/12
• CPC Class Codes: H01F 10/14 containing iron or nickel H01F10/126 , H01F10/13, H01F10/16 take precedence
• CPC Class Codes: H01F 10/16 containing cobalt H01F10/126 , H01F10/13 take precedence
• CPC Class Codes: H01F 10/324 Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]

Abstract

In order to dampen magnetization changes in magnetic devices, such as tunnel junctions (MTJ) used in high speed Magnetic Random Access Memory (MRAM), a transition metal selected from the 4d transition metals and 5d transition metals is alloyed into the magnetic layer to be dampened. In a preferred form, a magnetic permalloy layer is alloyed with osmium (Os) in an atomic concentration of between 4% and 15% of the alloy.

Claims

1. A magnetic device comprising:

a) at least one electrode; and

b) a free magnetic region comprising an alloy of at least one of Ni—

Fe, Co—

Fe, or Ni—

Co, and at least one transition metal selected from the group consisting of 4d transition metals and 5d transition metals, wherein said at least one transition metal is present in an atomic concentration of about 4% to about 15% of said alloy.

2. A magnetic device as set forth in claim 1, wherein said transition metal is osmium.

3. A magnetic device as set forth in claim 1, wherein said transition metal is niobium.

4. A magnetic device as set forth in claim 1, wherein said transition metal is ruthenium.

5. A magnetic device as set forth in claim 1, wherein said transition metal is rhodium.

6. A magnetic device as set forth in claim 1, wherein said transition metal is tantalum.

7. A magnetic device as set forth in claim 1, wherein said transition metal is platinum.

8. A magnetic device as set forth in claim 1, wherein said transition metal is iridium.

9. A magnetic device as set forth in claim 1, wherein said transition metal is palladium.

10. A magnetic device as set forth in claim 1, wherein said transition metal is rhenium.

11. A magnetic device as set forth in claim 1, wherein said transition metal is molybdenum.

12. A magnetic device as set forth in claim 1, wherein said transition metal is tungsten.

13. A magnetic device as set forth in claim 1 and operable as a spin valve, said spin valve comprising at least two magnetic layers and a nonmagnetic layer therebetween, said at least two magnetic layers having at least two stable magnetization relationships, at least one of said at least two magnetic layers comprising said alloy.

14. A magnetic device as set forth in claim 1 and operable as a magnetic tunnel junction device, said magnetic tunnel junction device comprising at least two magnetic layers and an insulating tunnel barrier layer therebetween, said at least two magnetic layers having at least two stable magnetization relationships, at least one of said at least two magnetic layers comprising said alloy.