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Influence of intermixing at the Ta/CoFeB interface on spin Hall angle in Ta/CoFeB/MgO heterostructures
- Publication Year :
- 2016
-
Abstract
- We investigate the spin Hall effect in perpendicularly magnetized Ta/Co40Fe40B20/MgO trilayers with Ta underlayers thicker than the spin diffusion length. The crystallographic structures of the Ta layer and Ta/CoFeB interface are examined in detail using X-ray diffraction and transmission electron microscopy. The thinnest Ta underlayer is amorphous, whereas for thicker Ta layers a disoriented tetragonal beta-phase appears. Effective spin-orbit torques are calculated based on harmonic Hall voltage measurements performed in a temperature range between 15 and 300 K. To account for the temperature dependence of damping-like and field-like torques, we extend the spin diffusion model by including an additional contribution from the Ta/CoFeB interface. Based on this approach, the temperature dependence of the spin Hall angle in the Ta underlayer and at Ta/CoFeB interface are determined separately. The results indicate an almost temperature-independent spin Hall angle of theta_SH-N = -0.2 in Ta and a strongly temperature-dependent theta_SH-I for the intermixed Ta/CoFeB interface.<br />Comment: 11 pages, 10 figures
- Subjects :
- Condensed Matter - Mesoscale and Nanoscale Physics
Subjects
Details
- Database :
- arXiv
- Publication Type :
- Report
- Accession number :
- edsarx.1612.03020
- Document Type :
- Working Paper