Dependence of Giant Tunnel Magnetoresistance of Sputtered CoFeB/MgO/CoFeB Magnetic Tunnel Junctions on MgO Barrier Thickness and Annealing Temperature
- 1 April 2005
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 44 (4L), L587
- https://doi.org/10.1143/jjap.44.l587
Abstract
We investigated the dependence of giant tunnel magnetoresistance (TMR) on the thickness of an MgO barrier and on the annealing temperature of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions deposited on SiO2/Si wafers. The resistance-area product exponentially increases with MgO thickness, indicating that the quality of MgO barriers is high in the investigated thickness range of 1.15–2.4 nm. High-resolution transmission electron microscope images show that annealing at 375°C results in the formation of crystalline CoFeB/MgO/CoFeB structures, even though CoFeB electrodes are amorphous in the as-sputtered state. The TMR ratio increases with annealing temperature and is as high as 260% at room temperature and 403% at 5 K.Keywords
This publication has 13 references indexed in Scilit:
- 230% room-temperature magnetoresistance in CoFeB∕MgO∕CoFeB magnetic tunnel junctionsApplied Physics Letters, 2005
- Large magnetoresistance in bcc and tunnel junctionsPhysical Review B, 2004
- Giant room-temperature magnetoresistance in single-crystal Fe/MgO/Fe magnetic tunnel junctionsNature Materials, 2004
- Giant tunnelling magnetoresistance at room temperature with MgO (100) tunnel barriersNature Materials, 2004
- 70% TMR at Room Temperature for SDT Sandwich Junctions With CoFeB as Free and Reference LayersIEEE Transactions on Magnetics, 2004
- Spin-dependent tunneling conductance ofsandwichesPhysical Review B, 2001
- Low resistance and high thermal stability of spin-dependent tunnel junctions with synthetic antiferromagnetic CoFe/Ru/CoFe pinned layersApplied Physics Letters, 2000
- Large Magnetoresistance at Room Temperature in Ferromagnetic Thin Film Tunnel JunctionsPhysical Review Letters, 1995
- Giant magnetic tunneling effect in Fe/Al2O3/Fe junctionJournal of Magnetism and Magnetic Materials, 1995
- Tunneling between ferromagnetic filmsPhysics Letters A, 1975