Electric breakdown in ultrathin MgO tunnel barrier junctions for spin-transfer torque switching
Abstract
Magnetic tunnel junctions for spin-transfer torque (STT) switching are prepared to investigate the dielectric breakdown. Intact and broken tunnel junctions are characterized by transport measurements prior to transmission electron microscopy analysis. The comparison to our previous model for thicker MgO tunnel barriers reveals a different breakdown mechanism arising from the high current densities in a STT device: instead of local pinhole formation at a constant rate, massive electromigration and heating leads to displacement of the junction material and voids are appearing. This is determined by element resolved energy dispersive x-ray spectroscopy and three dimensional tomographic reconstruction.
- Publication:
-
Applied Physics Letters
- Pub Date:
- December 2009
- DOI:
- 10.1063/1.3272268
- arXiv:
- arXiv:0907.3579
- Bibcode:
- 2009ApPhL..95w2119S
- Keywords:
-
- boron alloys;
- cobalt alloys;
- copper compounds;
- current density;
- electric breakdown;
- electromigration;
- iron alloys;
- magnesium compounds;
- magnetic multilayers;
- magnetic switching;
- magnetic tunnelling;
- manganese alloys;
- platinum alloys;
- ruthenium;
- tantalum;
- transmission electron microscopy;
- X-ray chemical analysis;
- 77.22.Jp;
- 75.70.Cn;
- 82.80.Ej;
- 66.30.Qa;
- 75.60.-d;
- Dielectric breakdown and space-charge effects;
- Magnetic properties of interfaces;
- X-ray Mossbauer and other gamma-ray spectroscopic analysis methods;
- Electromigration;
- Domain effects magnetization curves and hysteresis;
- Condensed Matter - Materials Science
- E-Print:
- doi:10.1063/1.3272268