Minimal thickness synthetic antiferromagnetic (SAF) structure with perpendicular magnetic anisotropy for STT-MRAM
First Claim
1. A synthetic antiferromagnetic (SAF) structure, comprising:
- (a) an AP2 reference layer with intrinsic perpendicular magnetic anisotropy;
(b) a CoFeB layer wherein perpendicular magnetic anisotropy is established by antiferromagnetic coupling with the AP2 reference layer through an antiferromagnetic (AF) coupling layer formed between the AP2 reference layer and CoFeB layer; and
(c) the AF coupling layer made of a non-magnetic material to give an AP2/AF coupling/CoFeB configuration or an CoFeB/AF coupling/AP2 configuration.
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Abstract
A synthetic antiferromagnetic (SAF) structure for a spintronic device is disclosed and has an AP2/antiferromagnetic (AF) coupling/CoFeB configuration. The SAF structure is thinned to reduce the fringing (Ho) field while maintaining high coercivity. The AP2 reference layer has intrinsic perpendicular magnetic anisotropy (PMA) and induces PMA in a thin CoFeB layer through AF coupling. In one embodiment, AF coupling is improved by inserting a Co dusting layer on top and bottom surfaces of a Ru AF coupling layer. When AP2 is (Co/Ni)4, and CoFeB thickness is 7.5 Angstroms, Ho is reduced to 125 Oe, Hc is 1000 Oe, and a balanced saturation magnetization-thickness product (Mst)=0.99 is achieved. The SAF structure may also be represented as FL2/AF coupling/CoFeB where FL2 is a ferromagnetic layer with intrinsic PMA.
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Citations
13 Claims
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1. A synthetic antiferromagnetic (SAF) structure, comprising:
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(a) an AP2 reference layer with intrinsic perpendicular magnetic anisotropy; (b) a CoFeB layer wherein perpendicular magnetic anisotropy is established by antiferromagnetic coupling with the AP2 reference layer through an antiferromagnetic (AF) coupling layer formed between the AP2 reference layer and CoFeB layer; and (c) the AF coupling layer made of a non-magnetic material to give an AP2/AF coupling/CoFeB configuration or an CoFeB/AF coupling/AP2 configuration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification