Effect of the oxide layer on current-induced spin-orbit torques in Hf vertical bar CoFeB vertical bar MgO and Hf vertical bar CoFeB vertical bar TaOx structures

Akyol M., Alzate J. G., Yu G., Upadhyaya P., Wong K. L., EKİCİBİL A., ...Daha Fazla

APPLIED PHYSICS LETTERS, cilt.106, sa.3, 2015 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 106 Sayı: 3
  • Basım Tarihi: 2015
  • Doi Numarası: 10.1063/1.4906352
  • Dergi Adı: APPLIED PHYSICS LETTERS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Çukurova Üniversitesi Adresli: Evet

Özet

We study the effect of the oxide layer on the current-induced spin-orbit torques (SOTs) in perpendicularly magnetized Hf|CoFeB|MgO (MgO-capped) or Hf|CoFeB|TaOx (TaOx-capped) structures. The effective fields corresponding to both the field-like and damping-like current-induced SOTs are characterized using electric transport measurements. Both torques are found to be significantly stronger in MgO-capped structures than those in TaOx-capped structures. The difference in field-like and damping-like SOTs in the different structures may be attributed to the different Rashba-like Hamiltonian, arising from the difference in the electric potential profiles across the oxide|ferromagnet interfaces in the two cases, as well as possible structural and oxidation differences in the underlying CoFeB and Hf layers. Our results show that the oxide layer in heavy-metal|ferromagnet|oxide trilayer structures has a very significant effect on the generated SOTs for manipulation of ferromagnetic layers. These findings could potentially be used to engineer SOT devices with enhanced current-induced switching efficiency. (C) 2015 AIP Publishing LLC.