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Bias Voltage Dependence of Magnetic Tunnel Junctions Comprising Double Barriers and CoFe/NiFeSiB/CoFe Free Layer.
- Source :
- IEEE Transactions on Magnetics; Oct2006, Vol. 42 Issue 10, p2649-2651, 3p, 2 Graphs
- Publication Year :
- 2006
-
Abstract
- The typical double-barrier magnetic tunnel junction (DMTJ) structure examined in this paper consists of a Ta 45/Ru9.5/IrMn 10/CoFe 7/AlO<subscript>x</subscript>/free layer/AlO<subscript>x</subscript>/CoFe 7/IrMn 10/Ru 60 (nm). The free layer consists of an Ni<subscript>16</subscript> Fe<subscript>62</subscript> Si<subscript>8</subscript> B<subscript>14</subscript> 7 nm, Co<subscript>90</subscript> Fe<subscript>10</subscript> (fcc) 7 nm, or CoFe t<subscript>1</subscript>/NiFeSiB t<subscript>2</subscript>/CoFe t<subscript>1</subscript> layer in which the thicknesses t<subscript>1</subscript> and t<subscript>2</subscript> are varied. The DMTJ with an NiFeSiB-free layer had a tunneling magnetoresistance (TMR) of 28%, an area-resistance product (RA) of 86 Ω 11 μm², a coercivity (H<subscript>c</subscript>) of 11 Oe, and an interlayer coupling field (H<subscript>i</subscript>) of 20 Oe. To improve the TMR ratio and RA, a DMTJ comprising an amorphous NiFeSiB layer that could partially substitute for the CoFe free layer was investigated. This hybrid DMTJ had a TMR of 30%, an RA of 68 k Ωμ m², and a H<subscript>c</subscript> of 11 Oe, but an increased H<subscript>i</subscript> of 37 Oe. We confirmed by atomic force microscopy and transmission electron microscopy that H<subscript>i</subscript> increased as the thickness of NiFeSiB decreased. When the amorphous NiFeSiB layer was thick, it was effective in retarding the columnar growth which usually induces a wavy interface. However, if the NiFeSiB layer was thin, the roughness was increased and H<subscript>i</subscript> became large because of the magnetostatic Néel coupling. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00189464
- Volume :
- 42
- Issue :
- 10
- Database :
- Complementary Index
- Journal :
- IEEE Transactions on Magnetics
- Publication Type :
- Academic Journal
- Accession number :
- 22739515
- Full Text :
- https://doi.org/10.1109/TMAG.2006.879720