Inductive determination of the optimum tunnel barrier thickness in magnetic tunneling junction stacks for spin torque memory applications
Abstract
We use pulsed inductive microwave magnetometry to study the precessional magnetization dynamics of the free layer in CoFeB/MgO/CoFeB based magnetic tunneling junction stacks with varying MgO barrier thickness. From the field dependence of the precession frequency we are able to derive the uniaxial anisotropy energy of the free layer and the exchange coupling between the free and the pinned layer. Furthermore the field dependence of the effective damping parameter is derived. Below a certain threshold barrier thickness we observe an increased effective damping for antiparallel orientation of free and pinned layer which would inhibit reversible low current density spin torque magnetization reversal. Such inductive measurements, in combination with wafer probe station based magneto transport experiments, allow a fast determination of the optimum tunnel barrier thickness range for spin torque memory applications in a lithography free process.
- Publication:
-
Journal of Applied Physics
- Pub Date:
- July 2011
- DOI:
- 10.1063/1.3610948
- arXiv:
- arXiv:1103.4248
- Bibcode:
- 2011JAP...110b3906S
- Keywords:
-
- boron alloys;
- cobalt alloys;
- exchange interactions (electron);
- galvanomagnetic effects;
- iron alloys;
- magnesium compounds;
- magnetic anisotropy;
- magnetic multilayers;
- magnetic tunnelling;
- 75.70.Cn;
- 75.47.-m;
- 75.30.Gw;
- 75.30.Et;
- Magnetic properties of interfaces;
- Magnetotransport phenomena;
- materials for magnetotransport;
- Magnetic anisotropy;
- Exchange and superexchange interactions;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 22 pages, 5 figures